diff --git a/.github/ISSUE_TEMPLATE/2.server_bug_report.yml b/.github/ISSUE_TEMPLATE/2.server_bug_report.yml
index a66f5c107..b868c672f 100644
--- a/.github/ISSUE_TEMPLATE/2.server_bug_report.yml
+++ b/.github/ISSUE_TEMPLATE/2.server_bug_report.yml
@@ -60,7 +60,7 @@ body:
         Any additional technical details you may have, like logs or error traces
       value: |
         If this is happening on your own Mastodon server, please fill out those:
-        - Ruby version: (from `ruby --version`, eg. v3.3.5)
+        - Ruby version: (from `ruby --version`, eg. v3.4.1)
         - Node.js version: (from `node --version`, eg. v20.18.0)
     validations:
       required: false
diff --git a/.github/ISSUE_TEMPLATE/3.troubleshooting.yml b/.github/ISSUE_TEMPLATE/3.troubleshooting.yml
index eeb74b160..fa9bfc7c8 100644
--- a/.github/ISSUE_TEMPLATE/3.troubleshooting.yml
+++ b/.github/ISSUE_TEMPLATE/3.troubleshooting.yml
@@ -61,7 +61,7 @@ body:
       value: |
         Please at least include those informations:
         - Operating system: (eg. Ubuntu 22.04)
-        - Ruby version: (from `ruby --version`, eg. v3.3.5)
+        - Ruby version: (from `ruby --version`, eg. v3.4.1)
         - Node.js version: (from `node --version`, eg. v20.18.0)
     validations:
       required: false
diff --git a/.github/renovate.json5 b/.github/renovate.json5
index 3d3499922..8a1067628 100644
--- a/.github/renovate.json5
+++ b/.github/renovate.json5
@@ -14,11 +14,6 @@
   // If we do not want a package to be grouped with others, we need to set its groupName
   // to `null` after any other rule set it to something.
   dependencyDashboardHeader: 'This issue lists Renovate updates and detected dependencies. Read the [Dependency Dashboard](https://docs.renovatebot.com/key-concepts/dashboard/) docs to learn more. Before approving any upgrade: read the description and comments in the [`renovate.json5` file](https://github.com/mastodon/mastodon/blob/main/.github/renovate.json5).',
-  constraints: {
-    // Mastodon should work on Ruby 3.4, but its test dependencies are currently uninstallable on Ruby 3.4.
-    // TODO: remove this once https://github.com/briandunn/flatware/issues/103 is fixed
-    ruby: '3.3',
-  },
   postUpdateOptions: ['yarnDedupeHighest'],
   packageRules: [
     {
diff --git a/.github/workflows/test-ruby.yml b/.github/workflows/test-ruby.yml
index 900faad07..4deb08d32 100644
--- a/.github/workflows/test-ruby.yml
+++ b/.github/workflows/test-ruby.yml
@@ -125,6 +125,7 @@ jobs:
       matrix:
         ruby-version:
           - '3.2'
+          - '3.3'
           - '.ruby-version'
     steps:
       - uses: actions/checkout@v4
@@ -226,6 +227,7 @@ jobs:
       matrix:
         ruby-version:
           - '3.2'
+          - '3.3'
           - '.ruby-version'
     steps:
       - uses: actions/checkout@v4
@@ -304,6 +306,7 @@ jobs:
       matrix:
         ruby-version:
           - '3.2'
+          - '3.3'
           - '.ruby-version'
 
     steps:
@@ -420,6 +423,7 @@ jobs:
       matrix:
         ruby-version:
           - '3.2'
+          - '3.3'
           - '.ruby-version'
         search-image:
           - docker.elastic.co/elasticsearch/elasticsearch:7.17.13
diff --git a/.ruby-version b/.ruby-version
index 9c25013db..47b322c97 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-3.3.6
+3.4.1
diff --git a/Dockerfile b/Dockerfile
index d80a4e155..97c7a9149 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -10,9 +10,9 @@
 ARG TARGETPLATFORM=${TARGETPLATFORM}
 ARG BUILDPLATFORM=${BUILDPLATFORM}
 
-# Ruby image to use for base image, change with [--build-arg RUBY_VERSION="3.3.x"]
+# Ruby image to use for base image, change with [--build-arg RUBY_VERSION="3.4.x"]
 # renovate: datasource=docker depName=docker.io/ruby
-ARG RUBY_VERSION="3.3.6"
+ARG RUBY_VERSION="3.4.1"
 # # Node version to use in base image, change with [--build-arg NODE_MAJOR_VERSION="20"]
 # renovate: datasource=node-version depName=node
 ARG NODE_MAJOR_VERSION="22"
@@ -20,7 +20,7 @@ ARG NODE_MAJOR_VERSION="22"
 ARG DEBIAN_VERSION="bookworm"
 # Node image to use for base image based on combined variables (ex: 20-bookworm-slim)
 FROM docker.io/node:${NODE_MAJOR_VERSION}-${DEBIAN_VERSION}-slim AS node
-# Ruby image to use for base image based on combined variables (ex: 3.3.x-slim-bookworm)
+# Ruby image to use for base image based on combined variables (ex: 3.4.x-slim-bookworm)
 FROM docker.io/ruby:${RUBY_VERSION}-slim-${DEBIAN_VERSION} AS ruby
 
 # Resulting version string is vX.X.X-MASTODON_VERSION_PRERELEASE+MASTODON_VERSION_METADATA
diff --git a/Gemfile b/Gemfile
index ad174cfdc..d2e6769ac 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 source 'https://rubygems.org'
-ruby '>= 3.2.0', '< 3.5'
+ruby '>= 3.2.0', '< 3.5.0'
 
 gem 'propshaft'
 gem 'puma', '~> 6.3'
diff --git a/Gemfile.lock b/Gemfile.lock
index f49de6bf3..afb06744e 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -238,11 +238,11 @@ GEM
     ffi-compiler (1.3.2)
       ffi (>= 1.15.5)
       rake
-    flatware (2.3.3)
+    flatware (2.3.4)
       drb
       thor (< 2.0)
-    flatware-rspec (2.3.3)
-      flatware (= 2.3.3)
+    flatware-rspec (2.3.4)
+      flatware (= 2.3.4)
       rspec (>= 3.6)
     fog-core (2.5.0)
       builder
@@ -1034,7 +1034,7 @@ DEPENDENCIES
   xorcist (~> 1.1)
 
 RUBY VERSION
-   ruby 3.3.6p108
+   ruby 3.4.1p0
 
 BUNDLED WITH
    2.6.2