diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6f775fcfa8..a53790afaf 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,101 @@
 
 All notable changes to this project will be documented in this file.
 
+## [4.2.7] - 2024-02-16
+
+### Fixed
+
+- Fix OmniAuth tests and edge cases in error handling ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/29201), [ClearlyClaire](https://github.com/mastodon/mastodon/pull/29207))
+- Fix new installs by upgrading to the latest release of the `nsa` gem, instead of a no longer existing commit ([mjankowski](https://github.com/mastodon/mastodon/pull/29065))
+
+### Security
+
+- Fix insufficient checking of remote posts ([GHSA-jhrq-qvrm-qr36](https://github.com/mastodon/mastodon/security/advisories/GHSA-jhrq-qvrm-qr36))
+
+## [4.2.6] - 2024-02-14
+
+### Security
+
+- Update the `sidekiq-unique-jobs` dependency (see [GHSA-cmh9-rx85-xj38](https://github.com/mhenrixon/sidekiq-unique-jobs/security/advisories/GHSA-cmh9-rx85-xj38))
+  In addition, we have disabled the web interface for `sidekiq-unique-jobs` out of caution.
+  If you need it, you can re-enable it by setting `ENABLE_SIDEKIQ_UNIQUE_JOBS_UI=true`.
+  If you only need to clear all locks, you can now use `bundle exec rake sidekiq_unique_jobs:delete_all_locks`.
+- Update the `nokogiri` dependency (see [GHSA-xc9x-jj77-9p9j](https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-xc9x-jj77-9p9j))
+- Disable administrative Doorkeeper routes ([ThisIsMissEm](https://github.com/mastodon/mastodon/pull/29187))
+- Fix ongoing streaming sessions not being invalidated when applications get deleted in some cases ([GHSA-7w3c-p9j8-mq3x](https://github.com/mastodon/mastodon/security/advisories/GHSA-7w3c-p9j8-mq3x))
+  In some rare cases, the streaming server was not notified of access tokens revocation on application deletion.
+- Change external authentication behavior to never reattach a new identity to an existing user by default ([GHSA-vm39-j3vx-pch3](https://github.com/mastodon/mastodon/security/advisories/GHSA-vm39-j3vx-pch3))
+  Up until now, Mastodon has allowed new identities from external authentication providers to attach to an existing local user based on their verified e-mail address.
+  This allowed upgrading users from a database-stored password to an external authentication provider, or move from one authentication provider to another.
+  However, this behavior may be unexpected, and means that when multiple authentication providers are configured, the overall security would be that of the least secure authentication provider.
+  For these reasons, this behavior is now locked under the `ALLOW_UNSAFE_AUTH_PROVIDER_REATTACH` environment variable.
+  In addition, regardless of this environment variable, Mastodon will refuse to attach two identities from the same authentication provider to the same account.
+
+## [4.2.5] - 2024-02-01
+
+### Security
+
+- Fix insufficient origin validation (CVE-2024-23832, [GHSA-3fjr-858r-92rw](https://github.com/mastodon/mastodon/security/advisories/GHSA-3fjr-858r-92rw))
+
+## [4.2.4] - 2024-01-24
+
+### Fixed
+
+- Fix error when processing remote files with unusually long names ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/28823))
+- Fix processing of compacted single-item JSON-LD collections ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/28816))
+- Retry 401 errors on replies fetching ([ShadowJonathan](https://github.com/mastodon/mastodon/pull/28788))
+- Fix `RecordNotUnique` errors in LinkCrawlWorker ([tribela](https://github.com/mastodon/mastodon/pull/28748))
+- Fix Mastodon not correctly processing HTTP Signatures with query strings ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/28443), [ClearlyClaire](https://github.com/mastodon/mastodon/pull/28476))
+- Fix potential redirection loop of streaming endpoint ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/28665))
+- Fix streaming API redirection ignoring the port of `streaming_api_base_url` ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/28558))
+- Fix error when processing link preview with an array as `inLanguage` ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/28252))
+- Fix unsupported time zone or locale preventing sign-up ([Gargron](https://github.com/mastodon/mastodon/pull/28035))
+- Fix "Hide these posts from home" list setting not refreshing when switching lists ([brianholley](https://github.com/mastodon/mastodon/pull/27763))
+- Fix missing background behind dismissable banner in web UI ([Gargron](https://github.com/mastodon/mastodon/pull/27479))
+- Fix line wrapping of language selection button with long locale codes ([gunchleoc](https://github.com/mastodon/mastodon/pull/27100), [ClearlyClaire](https://github.com/mastodon/mastodon/pull/27127))
+- Fix `Undo Announce` activity not being sent to non-follower authors ([MitarashiDango](https://github.com/mastodon/mastodon/pull/18482))
+- Fix N+1s because of association preloaders not actually getting called ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/28339))
+- Fix empty column explainer getting cropped under certain conditions ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/28337))
+- Fix `LinkCrawlWorker` error when encountering empty OEmbed response ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/28268))
+- Fix call to inefficient `delete_matched` cache method in domain blocks ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/28367))
+
+### Security
+
+- Add rate-limit of TOTP authentication attempts at controller level ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/28801))
+
+## [4.2.3] - 2023-12-05
+
+### Fixed
+
+- Fix dependency on `json-canonicalization` version that has been made unavailable since last release
+
+## [4.2.2] - 2023-12-04
+
+### Changed
+
+- Change dismissed banners to be stored server-side ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/27055))
+- Change GIF max matrix size error to explicitly mention GIF files ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/27927))
+- Change `Follow` activities delivery to bypass availability check ([ShadowJonathan](https://github.com/mastodon/mastodon/pull/27586))
+- Change single-column navigation notice to be displayed outside of the logo container ([renchap](https://github.com/mastodon/mastodon/pull/27462), [renchap](https://github.com/mastodon/mastodon/pull/27476))
+- Change Content-Security-Policy to be tighter on media paths ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/26889))
+- Change post language code to include country code when relevant ([gunchleoc](https://github.com/mastodon/mastodon/pull/27099), [ClearlyClaire](https://github.com/mastodon/mastodon/pull/27207))
+
+### Fixed
+
+- Fix upper border radius of onboarding columns ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/27890))
+- Fix incoming status creation date not being restricted to standard ISO8601 ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/27655), [ClearlyClaire](https://github.com/mastodon/mastodon/pull/28081))
+- Fix some posts from threads received out-of-order sometimes not being inserted into timelines ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/27653))
+- Fix posts from force-sensitized accounts being able to trend ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/27620))
+- Fix error when trying to delete already-deleted file with OpenStack Swift ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/27569))
+- Fix batch attachment deletion when using OpenStack Swift ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/27554))
+- Fix processing LDSigned activities from actors with unknown public keys ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/27474))
+- Fix error and incorrect URLs in `/api/v1/accounts/:id/featured_tags` for remote accounts ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/27459))
+- Fix report processing notice not mentioning the report number when performing a custom action ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/27442))
+- Fix handling of `inLanguage` attribute in preview card processing ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/27423))
+- Fix own posts being removed from home timeline when unfollowing a used hashtag ([kmycode](https://github.com/mastodon/mastodon/pull/27391))
+- Fix some link anchors being recognized as hashtags ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/27271), [ClearlyClaire](https://github.com/mastodon/mastodon/pull/27584))
+- Fix format-dependent redirects being cached regardless of requested format ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/27634))
+
 ## [4.2.1] - 2023-10-10
 
 ### Added
diff --git a/Gemfile.lock b/Gemfile.lock
index 00ca4663a8..0b53df82e0 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -505,7 +505,7 @@ GEM
     parslet (2.0.0)
     pastel (0.8.0)
       tty-color (~> 0.5)
-    pg (1.5.4)
+    pg (1.5.5)
     pghero (3.4.1)
       activerecord (>= 6)
     posix-spawn (0.3.15)
diff --git a/app/helpers/jsonld_helper.rb b/app/helpers/jsonld_helper.rb
index cc05b7a403..b0f2077db0 100644
--- a/app/helpers/jsonld_helper.rb
+++ b/app/helpers/jsonld_helper.rb
@@ -174,7 +174,19 @@ module JsonLdHelper
     build_request(uri, on_behalf_of, options: request_options).perform do |response|
       raise Mastodon::UnexpectedResponseError, response unless response_successful?(response) || response_error_unsalvageable?(response) || !raise_on_temporary_error
 
-      body_to_json(response.body_with_limit) if response.code == 200
+      body_to_json(response.body_with_limit) if response.code == 200 && valid_activitypub_content_type?(response)
+    end
+  end
+
+  def valid_activitypub_content_type?(response)
+    return true if response.mime_type == 'application/activity+json'
+
+    # When the mime type is `application/ld+json`, we need to check the profile,
+    # but `http.rb` does not parse it for us.
+    return false unless response.mime_type == 'application/ld+json'
+
+    response.headers[HTTP::Headers::CONTENT_TYPE]&.split(';')&.map(&:strip)&.any? do |str|
+      str.start_with?('profile="') && str[9...-1].split.include?('https://www.w3.org/ns/activitystreams')
     end
   end
 
diff --git a/app/javascript/flavours/glitch/features/account/components/follow_request_note.jsx b/app/javascript/flavours/glitch/features/account/components/follow_request_note.jsx
index 37d1508528..1e71ed1dcb 100644
--- a/app/javascript/flavours/glitch/features/account/components/follow_request_note.jsx
+++ b/app/javascript/flavours/glitch/features/account/components/follow_request_note.jsx
@@ -7,7 +7,6 @@ import CheckIcon from '@/material-icons/400-24px/check.svg?react';
 import CloseIcon from '@/material-icons/400-24px/close.svg?react';
 import { Icon }  from 'flavours/glitch/components/icon';
 
-
 export default class FollowRequestNote extends ImmutablePureComponent {
 
   static propTypes = {
diff --git a/app/javascript/flavours/glitch/features/account/components/header.jsx b/app/javascript/flavours/glitch/features/account/components/header.jsx
index 81ce989e99..ea56c9638b 100644
--- a/app/javascript/flavours/glitch/features/account/components/header.jsx
+++ b/app/javascript/flavours/glitch/features/account/components/header.jsx
@@ -9,7 +9,6 @@ import { withRouter } from 'react-router-dom';
 import ImmutablePropTypes from 'react-immutable-proptypes';
 import ImmutablePureComponent from 'react-immutable-pure-component';
 
-
 import CheckIcon from '@/material-icons/400-24px/check.svg?react';
 import LockIcon from '@/material-icons/400-24px/lock.svg?react';
 import MoreHorizIcon from '@/material-icons/400-24px/more_horiz.svg?react';
@@ -308,7 +307,7 @@ class Header extends ImmutablePureComponent {
       }
     }
 
-    const content          = { __html: account.get('note_emojified') };
+    const content         = { __html: account.get('note_emojified') };
     const displayNameHtml = { __html: account.get('display_name_html') };
     const fields          = account.get('fields');
     const isLocal         = account.get('acct').indexOf('@') === -1;
@@ -372,28 +371,29 @@ class Header extends ImmutablePureComponent {
             </div>
           )}
 
-          {signedIn && <AccountNoteContainer account={account} />}
-
           {!(suspended || hidden) && (
             <div className='account__header__extra'>
               <div className='account__header__bio'>
-                { fields.size > 0 && (
-                  <div className='account__header__fields'>
-                    {fields.map((pair, i) => (
-                      <dl key={i}>
-                        <dt dangerouslySetInnerHTML={{ __html: pair.get('name_emojified') }} title={pair.get('name')} />
-
-                        <dd className={pair.get('verified_at') && 'verified'} title={pair.get('value_plain')}>
-                          {pair.get('verified_at') && <span title={intl.formatMessage(messages.linkVerifiedOn, { date: intl.formatDate(pair.get('verified_at'), dateFormatOptions) })}><Icon id='check' icon={CheckIcon} className='verified__mark' /></span>} <span dangerouslySetInnerHTML={{ __html: pair.get('value_emojified') }} className='translate' />
-                        </dd>
-                      </dl>
-                    ))}
-                  </div>
-                )}
+                {(account.get('id') !== me && signedIn) && <AccountNoteContainer account={account} />}
 
                 {account.get('note').length > 0 && account.get('note') !== '<p></p>' && <div className='account__header__content translate' dangerouslySetInnerHTML={content} />}
 
-                <div className='account__header__joined'><FormattedMessage id='account.joined' defaultMessage='Joined {date}' values={{ date: intl.formatDate(account.get('created_at'), { year: 'numeric', month: 'short', day: '2-digit' }) }} /></div>
+                <div className='account__header__fields'>
+                  <dl>
+                    <dt><FormattedMessage id='account.joined_short' defaultMessage='Joined' /></dt>
+                    <dd>{intl.formatDate(account.get('created_at'), { year: 'numeric', month: 'short', day: '2-digit' })}</dd>
+                  </dl>
+
+                  {fields.map((pair, i) => (
+                    <dl key={i} className={classNames({ verified: pair.get('verified_at') })}>
+                      <dt dangerouslySetInnerHTML={{ __html: pair.get('name_emojified') }} title={pair.get('name')} className='translate' />
+
+                      <dd className='translate' title={pair.get('value_plain')}>
+                        {pair.get('verified_at') && <span title={intl.formatMessage(messages.linkVerifiedOn, { date: intl.formatDate(pair.get('verified_at'), dateFormatOptions) })}><Icon id='check' icon={CheckIcon} className='verified__mark' /></span>} <span dangerouslySetInnerHTML={{ __html: pair.get('value_emojified') }} />
+                      </dd>
+                    </dl>
+                  ))}
+                </div>
               </div>
             </div>
           )}
diff --git a/app/javascript/flavours/glitch/locales/en.json b/app/javascript/flavours/glitch/locales/en.json
index 68c6e3b194..829492c13c 100644
--- a/app/javascript/flavours/glitch/locales/en.json
+++ b/app/javascript/flavours/glitch/locales/en.json
@@ -3,7 +3,6 @@
   "account.disclaimer_full": "Information below may reflect the user's profile incompletely.",
   "account.follows": "Follows",
   "account.follows_you": "Follows you",
-  "account.joined": "Joined {date}",
   "account.suspended_disclaimer_full": "This user has been suspended by a moderator.",
   "account.view_full_profile": "View full profile",
   "advanced_options.icon_title": "Advanced options",
diff --git a/app/javascript/flavours/glitch/styles/components.scss b/app/javascript/flavours/glitch/styles/components.scss
index af23aca901..7df2a3aaff 100644
--- a/app/javascript/flavours/glitch/styles/components.scss
+++ b/app/javascript/flavours/glitch/styles/components.scss
@@ -5317,7 +5317,7 @@ a.status-card.compact:hover {
   border-bottom: 1px solid lighten($ui-base-color, 8%);
   display: flex;
   flex-direction: row;
-  padding: 10px 0;
+  padding: 8px 0;
 }
 
 .language-dropdown {
@@ -7986,6 +7986,7 @@ noscript {
     height: 145px;
     position: relative;
     background: darken($ui-base-color, 4%);
+    border-bottom: 1px solid lighten($ui-base-color, 8%);
 
     img {
       object-fit: cover;
@@ -7998,9 +7999,9 @@ noscript {
 
   &__bar {
     position: relative;
-    background: lighten($ui-base-color, 4%);
-    padding: 5px;
-    border-bottom: 1px solid lighten($ui-base-color, 12%);
+    padding: 0 20px;
+    padding-bottom: 16px; // glitch-soc addition for the different tabs design
+    border-bottom: 1px solid lighten($ui-base-color, 8%);
 
     .avatar {
       display: block;
@@ -8009,7 +8010,7 @@ noscript {
 
       .account__avatar {
         background: darken($ui-base-color, 8%);
-        border: 2px solid lighten($ui-base-color, 4%);
+        border: 2px solid $ui-base-color;
       }
     }
   }
@@ -8028,8 +8029,8 @@ noscript {
     display: flex;
     align-items: flex-start;
     justify-content: space-between;
-    padding: 7px 10px;
     margin-top: -55px;
+    padding-top: 10px;
     gap: 8px;
     overflow: hidden;
     margin-inline-start: -2px; // aligns the pfp with content below
@@ -8064,7 +8065,8 @@ noscript {
     }
 
     &__name {
-      padding: 5px 10px;
+      margin-top: 16px;
+      margin-bottom: 16px;
 
       .emojione {
         width: 22px;
@@ -8072,17 +8074,17 @@ noscript {
       }
 
       h1 {
-        font-size: 16px;
-        line-height: 24px;
+        font-size: 17px;
+        line-height: 22px;
         color: $primary-text-color;
-        font-weight: 500;
+        font-weight: 700;
         overflow: hidden;
         white-space: nowrap;
         text-overflow: ellipsis;
 
         small {
           display: block;
-          font-size: 14px;
+          font-size: 15px;
           color: $darker-text-color;
           font-weight: 400;
           overflow: hidden;
@@ -8108,63 +8110,97 @@ noscript {
   }
 
   &__bio {
-    overflow: hidden;
-    margin: 0 -5px;
-
     .account__header__content {
-      padding: 20px 15px;
-      padding-bottom: 5px;
       color: $primary-text-color;
     }
 
-    .account__header__joined {
-      font-size: 14px;
-      padding: 5px 15px;
-      color: $darker-text-color;
-
-      .columns-area--mobile & {
-        padding-inline-start: 20px;
-        padding-inline-end: 20px;
-      }
-    }
-
     .account__header__fields {
       margin: 0;
-      border-top: 1px solid lighten($ui-base-color, 12%);
+      margin-top: 16px;
+      border-radius: 4px;
+      background: darken($ui-base-color, 4%);
+      border: 0;
+
+      dl {
+        display: block;
+        padding: 8px 16px; // glitch-soc: padding purposefuly reduced
+        border-bottom-color: lighten($ui-base-color, 4%);
+      }
+
+      dd,
+      dt {
+        font-size: 13px;
+        line-height: 18px;
+        padding: 0;
+        text-align: initial;
+      }
+
+      dt {
+        width: auto;
+        background: transparent;
+        text-transform: uppercase;
+        color: $dark-text-color;
+      }
+
+      dd {
+        color: $darker-text-color;
+      }
 
       a {
         color: lighten($ui-highlight-color, 8%);
       }
 
-      dl:first-child .verified {
-        border-radius: 0 4px 0 0;
-      }
-
       .icon {
         width: 18px;
         height: 18px;
-        vertical-align: middle;
       }
 
-      dd {
-        display: flex;
-        align-items: center;
-        gap: 4px;
-      }
+      .verified {
+        border: 1px solid rgba($valid-value-color, 0.5);
+        margin-top: -1px;
 
-      .verified a {
-        color: $valid-value-color;
+        &:first-child {
+          border-top-left-radius: 4px;
+          border-top-right-radius: 4px;
+          margin-top: 0;
+        }
+
+        &:last-child {
+          border-bottom-left-radius: 4px;
+          border-bottom-right-radius: 4px;
+        }
+
+        dt,
+        dd {
+          color: $valid-value-color;
+        }
+
+        dd {
+          display: flex;
+          align-items: center;
+          gap: 4px;
+
+          span {
+            display: flex;
+          }
+        }
+
+        a {
+          color: $valid-value-color;
+        }
       }
     }
   }
 
   &__extra {
-    margin-top: 4px;
+    margin-top: 16px;
 
     &__links {
       font-size: 14px;
       color: $darker-text-color;
-      padding: 10px 0;
+      margin: 0 -10px;
+      padding-top: 16px;
+      padding-bottom: 10px;
 
       a {
         display: inline-block;
@@ -8182,14 +8218,10 @@ noscript {
   }
 
   &__account-note {
-    margin: 0 -5px;
-    padding: 10px 15px;
-    display: flex;
-    flex-direction: column;
+    color: $primary-text-color;
     font-size: 14px;
     font-weight: 400;
-    border-top: 1px solid lighten($ui-base-color, 12%);
-    border-bottom: 1px solid lighten($ui-base-color, 12%);
+    margin-bottom: 10px;
 
     label {
       display: block;
@@ -8200,23 +8232,12 @@ noscript {
       margin-bottom: 5px;
     }
 
-    &__content {
-      white-space: pre-wrap;
-      padding: 10px 0;
-    }
-
-    strong {
-      font-size: 12px;
-      font-weight: 500;
-      text-transform: uppercase;
-    }
-
     textarea {
       display: block;
       box-sizing: border-box;
       width: calc(100% + 20px);
       color: $secondary-text-color;
-      background: $ui-base-color;
+      background: transparent;
       padding: 10px;
       margin: 0 -10px;
       font-family: inherit;
@@ -8230,6 +8251,10 @@ noscript {
         color: $dark-text-color;
         opacity: 1;
       }
+
+      &:focus {
+        background: $ui-base-color;
+      }
     }
   }
 }
diff --git a/app/services/fetch_resource_service.rb b/app/services/fetch_resource_service.rb
index 71c6cca790..84c36f6a10 100644
--- a/app/services/fetch_resource_service.rb
+++ b/app/services/fetch_resource_service.rb
@@ -44,7 +44,7 @@ class FetchResourceService < BaseService
     @response_code = response.code
     return nil if response.code != 200
 
-    if ['application/activity+json', 'application/ld+json'].include?(response.mime_type)
+    if valid_activitypub_content_type?(response)
       body = response.body_with_limit
       json = body_to_json(body)
 
diff --git a/docker-compose.yml b/docker-compose.yml
index 93451d9611..154754d45f 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -56,7 +56,7 @@ services:
 
   web:
     build: .
-    image: ghcr.io/mastodon/mastodon:v4.2.0
+    image: ghcr.io/mastodon/mastodon:v4.2.7
     restart: always
     env_file: .env.production
     command: bundle exec puma -C config/puma.rb
@@ -77,7 +77,7 @@ services:
 
   streaming:
     build: .
-    image: ghcr.io/mastodon/mastodon:v4.2.0
+    image: ghcr.io/mastodon/mastodon:v4.2.7
     restart: always
     env_file: .env.production
     command: node ./streaming
@@ -95,7 +95,7 @@ services:
 
   sidekiq:
     build: .
-    image: ghcr.io/mastodon/mastodon:v4.2.0
+    image: ghcr.io/mastodon/mastodon:v4.2.7
     restart: always
     env_file: .env.production
     command: bundle exec sidekiq
diff --git a/lib/mastodon/version.rb b/lib/mastodon/version.rb
index efc643fb44..5d7f3d4d0c 100644
--- a/lib/mastodon/version.rb
+++ b/lib/mastodon/version.rb
@@ -17,7 +17,7 @@ module Mastodon
     end
 
     def default_prerelease
-      'alpha.2'
+      'alpha.3'
     end
 
     def prerelease
diff --git a/spec/helpers/json_ld_helper_spec.rb b/spec/helpers/json_ld_helper_spec.rb
index 99857278a1..4855085027 100644
--- a/spec/helpers/json_ld_helper_spec.rb
+++ b/spec/helpers/json_ld_helper_spec.rb
@@ -56,15 +56,15 @@ describe JsonLdHelper do
   describe '#fetch_resource' do
     context 'when the second argument is false' do
       it 'returns resource even if the retrieved ID and the given URI does not match' do
-        stub_request(:get, 'https://bob.test/').to_return body: '{"id": "https://alice.test/"}'
-        stub_request(:get, 'https://alice.test/').to_return body: '{"id": "https://alice.test/"}'
+        stub_request(:get, 'https://bob.test/').to_return(body: '{"id": "https://alice.test/"}', headers: { 'Content-Type': 'application/activity+json' })
+        stub_request(:get, 'https://alice.test/').to_return(body: '{"id": "https://alice.test/"}', headers: { 'Content-Type': 'application/activity+json' })
 
         expect(fetch_resource('https://bob.test/', false)).to eq({ 'id' => 'https://alice.test/' })
       end
 
       it 'returns nil if the object identified by the given URI and the object identified by the retrieved ID does not match' do
-        stub_request(:get, 'https://mallory.test/').to_return body: '{"id": "https://marvin.test/"}'
-        stub_request(:get, 'https://marvin.test/').to_return body: '{"id": "https://alice.test/"}'
+        stub_request(:get, 'https://mallory.test/').to_return(body: '{"id": "https://marvin.test/"}', headers: { 'Content-Type': 'application/activity+json' })
+        stub_request(:get, 'https://marvin.test/').to_return(body: '{"id": "https://alice.test/"}', headers: { 'Content-Type': 'application/activity+json' })
 
         expect(fetch_resource('https://mallory.test/', false)).to be_nil
       end
@@ -72,7 +72,7 @@ describe JsonLdHelper do
 
     context 'when the second argument is true' do
       it 'returns nil if the retrieved ID and the given URI does not match' do
-        stub_request(:get, 'https://mallory.test/').to_return body: '{"id": "https://alice.test/"}'
+        stub_request(:get, 'https://mallory.test/').to_return(body: '{"id": "https://alice.test/"}', headers: { 'Content-Type': 'application/activity+json' })
         expect(fetch_resource('https://mallory.test/', true)).to be_nil
       end
     end
@@ -80,12 +80,12 @@ describe JsonLdHelper do
 
   describe '#fetch_resource_without_id_validation' do
     it 'returns nil if the status code is not 200' do
-      stub_request(:get, 'https://host.test/').to_return status: 400, body: '{}'
+      stub_request(:get, 'https://host.test/').to_return(status: 400, body: '{}', headers: { 'Content-Type': 'application/activity+json' })
       expect(fetch_resource_without_id_validation('https://host.test/')).to be_nil
     end
 
     it 'returns hash' do
-      stub_request(:get, 'https://host.test/').to_return status: 200, body: '{}'
+      stub_request(:get, 'https://host.test/').to_return(status: 200, body: '{}', headers: { 'Content-Type': 'application/activity+json' })
       expect(fetch_resource_without_id_validation('https://host.test/')).to eq({})
     end
   end
diff --git a/spec/lib/activitypub/activity/announce_spec.rb b/spec/lib/activitypub/activity/announce_spec.rb
index 8ad892975d..b556bfd6c2 100644
--- a/spec/lib/activitypub/activity/announce_spec.rb
+++ b/spec/lib/activitypub/activity/announce_spec.rb
@@ -35,7 +35,7 @@ RSpec.describe ActivityPub::Activity::Announce do
     context 'when sender is followed by a local account' do
       before do
         Fabricate(:account).follow!(sender)
-        stub_request(:get, 'https://example.com/actor/hello-world').to_return(body: Oj.dump(unknown_object_json))
+        stub_request(:get, 'https://example.com/actor/hello-world').to_return(body: Oj.dump(unknown_object_json), headers: { 'Content-Type': 'application/activity+json' })
         subject.perform
       end
 
@@ -120,7 +120,7 @@ RSpec.describe ActivityPub::Activity::Announce do
       let(:object_json) { 'https://example.com/actor/hello-world' }
 
       before do
-        stub_request(:get, 'https://example.com/actor/hello-world').to_return(body: Oj.dump(unknown_object_json))
+        stub_request(:get, 'https://example.com/actor/hello-world').to_return(body: Oj.dump(unknown_object_json), headers: { 'Content-Type': 'application/activity+json' })
       end
 
       context 'when the relay is enabled' do
diff --git a/spec/services/activitypub/fetch_featured_collection_service_spec.rb b/spec/services/activitypub/fetch_featured_collection_service_spec.rb
index b9e95b825f..dab204406b 100644
--- a/spec/services/activitypub/fetch_featured_collection_service_spec.rb
+++ b/spec/services/activitypub/fetch_featured_collection_service_spec.rb
@@ -72,11 +72,11 @@ RSpec.describe ActivityPub::FetchFeaturedCollectionService, type: :service do
 
   shared_examples 'sets pinned posts' do
     before do
-      stub_request(:get, 'https://example.com/account/pinned/known').to_return(status: 200, body: Oj.dump(status_json_pinned_known))
-      stub_request(:get, 'https://example.com/account/pinned/unknown-inlined').to_return(status: 200, body: Oj.dump(status_json_pinned_unknown_inlined))
+      stub_request(:get, 'https://example.com/account/pinned/known').to_return(status: 200, body: Oj.dump(status_json_pinned_known), headers: { 'Content-Type': 'application/activity+json' })
+      stub_request(:get, 'https://example.com/account/pinned/unknown-inlined').to_return(status: 200, body: Oj.dump(status_json_pinned_unknown_inlined), headers: { 'Content-Type': 'application/activity+json' })
       stub_request(:get, 'https://example.com/account/pinned/unknown-unreachable').to_return(status: 404)
-      stub_request(:get, 'https://example.com/account/pinned/unknown-reachable').to_return(status: 200, body: Oj.dump(status_json_pinned_unknown_reachable))
-      stub_request(:get, 'https://example.com/account/collections/featured').to_return(status: 200, body: Oj.dump(featured_with_null))
+      stub_request(:get, 'https://example.com/account/pinned/unknown-reachable').to_return(status: 200, body: Oj.dump(status_json_pinned_unknown_reachable), headers: { 'Content-Type': 'application/activity+json' })
+      stub_request(:get, 'https://example.com/account/collections/featured').to_return(status: 200, body: Oj.dump(featured_with_null), headers: { 'Content-Type': 'application/activity+json' })
 
       subject.call(actor, note: true, hashtag: false)
     end
@@ -94,7 +94,7 @@ RSpec.describe ActivityPub::FetchFeaturedCollectionService, type: :service do
   describe '#call' do
     context 'when the endpoint is a Collection' do
       before do
-        stub_request(:get, actor.featured_collection_url).to_return(status: 200, body: Oj.dump(payload))
+        stub_request(:get, actor.featured_collection_url).to_return(status: 200, body: Oj.dump(payload), headers: { 'Content-Type': 'application/activity+json' })
       end
 
       it_behaves_like 'sets pinned posts'
@@ -111,7 +111,7 @@ RSpec.describe ActivityPub::FetchFeaturedCollectionService, type: :service do
       end
 
       before do
-        stub_request(:get, actor.featured_collection_url).to_return(status: 200, body: Oj.dump(payload))
+        stub_request(:get, actor.featured_collection_url).to_return(status: 200, body: Oj.dump(payload), headers: { 'Content-Type': 'application/activity+json' })
       end
 
       it_behaves_like 'sets pinned posts'
@@ -120,7 +120,7 @@ RSpec.describe ActivityPub::FetchFeaturedCollectionService, type: :service do
         let(:items) { 'https://example.com/account/pinned/unknown-reachable' }
 
         before do
-          stub_request(:get, 'https://example.com/account/pinned/unknown-reachable').to_return(status: 200, body: Oj.dump(status_json_pinned_unknown_reachable))
+          stub_request(:get, 'https://example.com/account/pinned/unknown-reachable').to_return(status: 200, body: Oj.dump(status_json_pinned_unknown_reachable), headers: { 'Content-Type': 'application/activity+json' })
           subject.call(actor, note: true, hashtag: false)
         end
 
@@ -147,7 +147,7 @@ RSpec.describe ActivityPub::FetchFeaturedCollectionService, type: :service do
       end
 
       before do
-        stub_request(:get, actor.featured_collection_url).to_return(status: 200, body: Oj.dump(payload))
+        stub_request(:get, actor.featured_collection_url).to_return(status: 200, body: Oj.dump(payload), headers: { 'Content-Type': 'application/activity+json' })
       end
 
       it_behaves_like 'sets pinned posts'
@@ -156,7 +156,7 @@ RSpec.describe ActivityPub::FetchFeaturedCollectionService, type: :service do
         let(:items) { 'https://example.com/account/pinned/unknown-reachable' }
 
         before do
-          stub_request(:get, 'https://example.com/account/pinned/unknown-reachable').to_return(status: 200, body: Oj.dump(status_json_pinned_unknown_reachable))
+          stub_request(:get, 'https://example.com/account/pinned/unknown-reachable').to_return(status: 200, body: Oj.dump(status_json_pinned_unknown_reachable), headers: { 'Content-Type': 'application/activity+json' })
           subject.call(actor, note: true, hashtag: false)
         end
 
diff --git a/spec/services/activitypub/fetch_featured_tags_collection_service_spec.rb b/spec/services/activitypub/fetch_featured_tags_collection_service_spec.rb
index 071e4d92d5..638278a10e 100644
--- a/spec/services/activitypub/fetch_featured_tags_collection_service_spec.rb
+++ b/spec/services/activitypub/fetch_featured_tags_collection_service_spec.rb
@@ -38,7 +38,7 @@ RSpec.describe ActivityPub::FetchFeaturedTagsCollectionService, type: :service d
   describe '#call' do
     context 'when the endpoint is a Collection' do
       before do
-        stub_request(:get, collection_url).to_return(status: 200, body: Oj.dump(payload))
+        stub_request(:get, collection_url).to_return(status: 200, body: Oj.dump(payload), headers: { 'Content-Type': 'application/activity+json' })
       end
 
       it_behaves_like 'sets featured tags'
@@ -46,7 +46,7 @@ RSpec.describe ActivityPub::FetchFeaturedTagsCollectionService, type: :service d
 
     context 'when the account already has featured tags' do
       before do
-        stub_request(:get, collection_url).to_return(status: 200, body: Oj.dump(payload))
+        stub_request(:get, collection_url).to_return(status: 200, body: Oj.dump(payload), headers: { 'Content-Type': 'application/activity+json' })
 
         actor.featured_tags.create!(name: 'FoO')
         actor.featured_tags.create!(name: 'baz')
@@ -67,7 +67,7 @@ RSpec.describe ActivityPub::FetchFeaturedTagsCollectionService, type: :service d
       end
 
       before do
-        stub_request(:get, collection_url).to_return(status: 200, body: Oj.dump(payload))
+        stub_request(:get, collection_url).to_return(status: 200, body: Oj.dump(payload), headers: { 'Content-Type': 'application/activity+json' })
       end
 
       it_behaves_like 'sets featured tags'
@@ -88,7 +88,7 @@ RSpec.describe ActivityPub::FetchFeaturedTagsCollectionService, type: :service d
       end
 
       before do
-        stub_request(:get, collection_url).to_return(status: 200, body: Oj.dump(payload))
+        stub_request(:get, collection_url).to_return(status: 200, body: Oj.dump(payload), headers: { 'Content-Type': 'application/activity+json' })
       end
 
       it_behaves_like 'sets featured tags'
diff --git a/spec/services/activitypub/fetch_remote_account_service_spec.rb b/spec/services/activitypub/fetch_remote_account_service_spec.rb
index f33a928da6..42badde051 100644
--- a/spec/services/activitypub/fetch_remote_account_service_spec.rb
+++ b/spec/services/activitypub/fetch_remote_account_service_spec.rb
@@ -44,7 +44,7 @@ RSpec.describe ActivityPub::FetchRemoteAccountService, type: :service do
       before do
         actor[:inbox] = nil
 
-        stub_request(:get, 'https://example.com/alice').to_return(body: Oj.dump(actor))
+        stub_request(:get, 'https://example.com/alice').to_return(body: Oj.dump(actor), headers: { 'Content-Type': 'application/activity+json' })
         stub_request(:get, 'https://example.com/.well-known/webfinger?resource=acct:alice@example.com').to_return(body: Oj.dump(webfinger), headers: { 'Content-Type': 'application/jrd+json' })
       end
 
@@ -67,7 +67,7 @@ RSpec.describe ActivityPub::FetchRemoteAccountService, type: :service do
       let!(:webfinger) { { subject: 'acct:alice@example.com', links: [{ rel: 'self', href: 'https://example.com/alice' }] } }
 
       before do
-        stub_request(:get, 'https://example.com/alice').to_return(body: Oj.dump(actor))
+        stub_request(:get, 'https://example.com/alice').to_return(body: Oj.dump(actor), headers: { 'Content-Type': 'application/activity+json' })
         stub_request(:get, 'https://example.com/.well-known/webfinger?resource=acct:alice@example.com').to_return(body: Oj.dump(webfinger), headers: { 'Content-Type': 'application/jrd+json' })
       end
 
@@ -93,7 +93,7 @@ RSpec.describe ActivityPub::FetchRemoteAccountService, type: :service do
       let!(:webfinger) { { subject: 'acct:alice@iscool.af', links: [{ rel: 'self', href: 'https://example.com/alice' }] } }
 
       before do
-        stub_request(:get, 'https://example.com/alice').to_return(body: Oj.dump(actor))
+        stub_request(:get, 'https://example.com/alice').to_return(body: Oj.dump(actor), headers: { 'Content-Type': 'application/activity+json' })
         stub_request(:get, 'https://example.com/.well-known/webfinger?resource=acct:alice@example.com').to_return(body: Oj.dump(webfinger), headers: { 'Content-Type': 'application/jrd+json' })
         stub_request(:get, 'https://iscool.af/.well-known/webfinger?resource=acct:alice@iscool.af').to_return(body: Oj.dump(webfinger), headers: { 'Content-Type': 'application/jrd+json' })
       end
@@ -125,7 +125,7 @@ RSpec.describe ActivityPub::FetchRemoteAccountService, type: :service do
       let!(:webfinger) { { subject: 'acct:alice@example.com', links: [{ rel: 'self', href: 'https://example.com/bob' }] } }
 
       before do
-        stub_request(:get, 'https://example.com/alice').to_return(body: Oj.dump(actor))
+        stub_request(:get, 'https://example.com/alice').to_return(body: Oj.dump(actor), headers: { 'Content-Type': 'application/activity+json' })
         stub_request(:get, 'https://example.com/.well-known/webfinger?resource=acct:alice@example.com').to_return(body: Oj.dump(webfinger), headers: { 'Content-Type': 'application/jrd+json' })
       end
 
@@ -148,7 +148,7 @@ RSpec.describe ActivityPub::FetchRemoteAccountService, type: :service do
       let!(:webfinger) { { subject: 'acct:alice@iscool.af', links: [{ rel: 'self', href: 'https://example.com/bob' }] } }
 
       before do
-        stub_request(:get, 'https://example.com/alice').to_return(body: Oj.dump(actor))
+        stub_request(:get, 'https://example.com/alice').to_return(body: Oj.dump(actor), headers: { 'Content-Type': 'application/activity+json' })
         stub_request(:get, 'https://example.com/.well-known/webfinger?resource=acct:alice@example.com').to_return(body: Oj.dump(webfinger), headers: { 'Content-Type': 'application/jrd+json' })
         stub_request(:get, 'https://iscool.af/.well-known/webfinger?resource=acct:alice@iscool.af').to_return(body: Oj.dump(webfinger), headers: { 'Content-Type': 'application/jrd+json' })
       end
diff --git a/spec/services/activitypub/fetch_remote_actor_service_spec.rb b/spec/services/activitypub/fetch_remote_actor_service_spec.rb
index 944a2f8b1c..6d264b7b82 100644
--- a/spec/services/activitypub/fetch_remote_actor_service_spec.rb
+++ b/spec/services/activitypub/fetch_remote_actor_service_spec.rb
@@ -44,7 +44,7 @@ RSpec.describe ActivityPub::FetchRemoteActorService, type: :service do
       before do
         actor[:inbox] = nil
 
-        stub_request(:get, 'https://example.com/alice').to_return(body: Oj.dump(actor))
+        stub_request(:get, 'https://example.com/alice').to_return(body: Oj.dump(actor), headers: { 'Content-Type': 'application/activity+json' })
         stub_request(:get, 'https://example.com/.well-known/webfinger?resource=acct:alice@example.com').to_return(body: Oj.dump(webfinger), headers: { 'Content-Type': 'application/jrd+json' })
       end
 
@@ -67,7 +67,7 @@ RSpec.describe ActivityPub::FetchRemoteActorService, type: :service do
       let!(:webfinger) { { subject: 'acct:alice@example.com', links: [{ rel: 'self', href: 'https://example.com/alice' }] } }
 
       before do
-        stub_request(:get, 'https://example.com/alice').to_return(body: Oj.dump(actor))
+        stub_request(:get, 'https://example.com/alice').to_return(body: Oj.dump(actor), headers: { 'Content-Type': 'application/activity+json' })
         stub_request(:get, 'https://example.com/.well-known/webfinger?resource=acct:alice@example.com').to_return(body: Oj.dump(webfinger), headers: { 'Content-Type': 'application/jrd+json' })
       end
 
@@ -93,7 +93,7 @@ RSpec.describe ActivityPub::FetchRemoteActorService, type: :service do
       let!(:webfinger) { { subject: 'acct:alice@iscool.af', links: [{ rel: 'self', href: 'https://example.com/alice' }] } }
 
       before do
-        stub_request(:get, 'https://example.com/alice').to_return(body: Oj.dump(actor))
+        stub_request(:get, 'https://example.com/alice').to_return(body: Oj.dump(actor), headers: { 'Content-Type': 'application/activity+json' })
         stub_request(:get, 'https://example.com/.well-known/webfinger?resource=acct:alice@example.com').to_return(body: Oj.dump(webfinger), headers: { 'Content-Type': 'application/jrd+json' })
         stub_request(:get, 'https://iscool.af/.well-known/webfinger?resource=acct:alice@iscool.af').to_return(body: Oj.dump(webfinger), headers: { 'Content-Type': 'application/jrd+json' })
       end
@@ -125,7 +125,7 @@ RSpec.describe ActivityPub::FetchRemoteActorService, type: :service do
       let!(:webfinger) { { subject: 'acct:alice@example.com', links: [{ rel: 'self', href: 'https://example.com/bob' }] } }
 
       before do
-        stub_request(:get, 'https://example.com/alice').to_return(body: Oj.dump(actor))
+        stub_request(:get, 'https://example.com/alice').to_return(body: Oj.dump(actor), headers: { 'Content-Type': 'application/activity+json' })
         stub_request(:get, 'https://example.com/.well-known/webfinger?resource=acct:alice@example.com').to_return(body: Oj.dump(webfinger), headers: { 'Content-Type': 'application/jrd+json' })
       end
 
@@ -148,7 +148,7 @@ RSpec.describe ActivityPub::FetchRemoteActorService, type: :service do
       let!(:webfinger) { { subject: 'acct:alice@iscool.af', links: [{ rel: 'self', href: 'https://example.com/bob' }] } }
 
       before do
-        stub_request(:get, 'https://example.com/alice').to_return(body: Oj.dump(actor))
+        stub_request(:get, 'https://example.com/alice').to_return(body: Oj.dump(actor), headers: { 'Content-Type': 'application/activity+json' })
         stub_request(:get, 'https://example.com/.well-known/webfinger?resource=acct:alice@example.com').to_return(body: Oj.dump(webfinger), headers: { 'Content-Type': 'application/jrd+json' })
         stub_request(:get, 'https://iscool.af/.well-known/webfinger?resource=acct:alice@iscool.af').to_return(body: Oj.dump(webfinger), headers: { 'Content-Type': 'application/jrd+json' })
       end
diff --git a/spec/services/activitypub/fetch_remote_key_service_spec.rb b/spec/services/activitypub/fetch_remote_key_service_spec.rb
index 0b14da4f44..478778cc9f 100644
--- a/spec/services/activitypub/fetch_remote_key_service_spec.rb
+++ b/spec/services/activitypub/fetch_remote_key_service_spec.rb
@@ -50,7 +50,7 @@ RSpec.describe ActivityPub::FetchRemoteKeyService, type: :service do
   end
 
   before do
-    stub_request(:get, 'https://example.com/alice').to_return(body: Oj.dump(actor))
+    stub_request(:get, 'https://example.com/alice').to_return(body: Oj.dump(actor), headers: { 'Content-Type': 'application/activity+json' })
     stub_request(:get, 'https://example.com/.well-known/webfinger?resource=acct:alice@example.com').to_return(body: Oj.dump(webfinger), headers: { 'Content-Type': 'application/jrd+json' })
   end
 
@@ -59,7 +59,7 @@ RSpec.describe ActivityPub::FetchRemoteKeyService, type: :service do
 
     context 'when the key is a sub-object from the actor' do
       before do
-        stub_request(:get, public_key_id).to_return(body: Oj.dump(actor))
+        stub_request(:get, public_key_id).to_return(body: Oj.dump(actor), headers: { 'Content-Type': 'application/activity+json' })
       end
 
       it 'returns the expected account' do
@@ -71,7 +71,7 @@ RSpec.describe ActivityPub::FetchRemoteKeyService, type: :service do
       let(:public_key_id) { 'https://example.com/alice-public-key.json' }
 
       before do
-        stub_request(:get, public_key_id).to_return(body: Oj.dump(key_json.merge({ '@context': ['https://www.w3.org/ns/activitystreams', 'https://w3id.org/security/v1'] })))
+        stub_request(:get, public_key_id).to_return(body: Oj.dump(key_json.merge({ '@context': ['https://www.w3.org/ns/activitystreams', 'https://w3id.org/security/v1'] })), headers: { 'Content-Type': 'application/activity+json' })
       end
 
       it 'returns the expected account' do
@@ -84,7 +84,7 @@ RSpec.describe ActivityPub::FetchRemoteKeyService, type: :service do
       let(:actor_public_key) { 'https://example.com/alice-public-key.json' }
 
       before do
-        stub_request(:get, public_key_id).to_return(body: Oj.dump(key_json.merge({ '@context': ['https://www.w3.org/ns/activitystreams', 'https://w3id.org/security/v1'] })))
+        stub_request(:get, public_key_id).to_return(body: Oj.dump(key_json.merge({ '@context': ['https://www.w3.org/ns/activitystreams', 'https://w3id.org/security/v1'] })), headers: { 'Content-Type': 'application/activity+json' })
       end
 
       it 'returns the nil' do
diff --git a/spec/services/activitypub/fetch_replies_service_spec.rb b/spec/services/activitypub/fetch_replies_service_spec.rb
index a76b996c20..8e1f606e26 100644
--- a/spec/services/activitypub/fetch_replies_service_spec.rb
+++ b/spec/services/activitypub/fetch_replies_service_spec.rb
@@ -58,7 +58,7 @@ RSpec.describe ActivityPub::FetchRepliesService, type: :service do
 
       context 'when passing the URL to the collection' do
         before do
-          stub_request(:get, collection_uri).to_return(status: 200, body: Oj.dump(payload))
+          stub_request(:get, collection_uri).to_return(status: 200, body: Oj.dump(payload), headers: { 'Content-Type': 'application/activity+json' })
         end
 
         it 'spawns workers for up to 5 replies on the same server' do
@@ -93,7 +93,7 @@ RSpec.describe ActivityPub::FetchRepliesService, type: :service do
 
       context 'when passing the URL to the collection' do
         before do
-          stub_request(:get, collection_uri).to_return(status: 200, body: Oj.dump(payload))
+          stub_request(:get, collection_uri).to_return(status: 200, body: Oj.dump(payload), headers: { 'Content-Type': 'application/activity+json' })
         end
 
         it 'spawns workers for up to 5 replies on the same server' do
@@ -132,7 +132,7 @@ RSpec.describe ActivityPub::FetchRepliesService, type: :service do
 
       context 'when passing the URL to the collection' do
         before do
-          stub_request(:get, collection_uri).to_return(status: 200, body: Oj.dump(payload))
+          stub_request(:get, collection_uri).to_return(status: 200, body: Oj.dump(payload), headers: { 'Content-Type': 'application/activity+json' })
         end
 
         it 'spawns workers for up to 5 replies on the same server' do
diff --git a/spec/services/activitypub/synchronize_followers_service_spec.rb b/spec/services/activitypub/synchronize_followers_service_spec.rb
index c9a513e24b..f62376ab95 100644
--- a/spec/services/activitypub/synchronize_followers_service_spec.rb
+++ b/spec/services/activitypub/synchronize_followers_service_spec.rb
@@ -60,7 +60,7 @@ RSpec.describe ActivityPub::SynchronizeFollowersService, type: :service do
   describe '#call' do
     context 'when the endpoint is a Collection of actor URIs' do
       before do
-        stub_request(:get, collection_uri).to_return(status: 200, body: Oj.dump(payload))
+        stub_request(:get, collection_uri).to_return(status: 200, body: Oj.dump(payload), headers: { 'Content-Type': 'application/activity+json' })
       end
 
       it_behaves_like 'synchronizes followers'
@@ -77,7 +77,7 @@ RSpec.describe ActivityPub::SynchronizeFollowersService, type: :service do
       end
 
       before do
-        stub_request(:get, collection_uri).to_return(status: 200, body: Oj.dump(payload))
+        stub_request(:get, collection_uri).to_return(status: 200, body: Oj.dump(payload), headers: { 'Content-Type': 'application/activity+json' })
       end
 
       it_behaves_like 'synchronizes followers'
@@ -98,7 +98,7 @@ RSpec.describe ActivityPub::SynchronizeFollowersService, type: :service do
       end
 
       before do
-        stub_request(:get, collection_uri).to_return(status: 200, body: Oj.dump(payload))
+        stub_request(:get, collection_uri).to_return(status: 200, body: Oj.dump(payload), headers: { 'Content-Type': 'application/activity+json' })
       end
 
       it_behaves_like 'synchronizes followers'
diff --git a/spec/workers/activitypub/fetch_replies_worker_spec.rb b/spec/workers/activitypub/fetch_replies_worker_spec.rb
index ff4d049a26..2d080e286e 100644
--- a/spec/workers/activitypub/fetch_replies_worker_spec.rb
+++ b/spec/workers/activitypub/fetch_replies_worker_spec.rb
@@ -21,7 +21,7 @@ describe ActivityPub::FetchRepliesWorker do
 
   describe 'perform' do
     it 'performs a request if the collection URI is from the same host' do
-      stub_request(:get, 'https://example.com/statuses_replies/1').to_return(status: 200, body: json)
+      stub_request(:get, 'https://example.com/statuses_replies/1').to_return(status: 200, body: json, headers: { 'Content-Type': 'application/activity+json' })
       subject.perform(status.id, 'https://example.com/statuses_replies/1')
       expect(a_request(:get, 'https://example.com/statuses_replies/1')).to have_been_made.once
     end