diff --git a/.ruby-version b/.ruby-version
index a0891f56..fa7adc7a 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-3.3.4
+3.3.5
diff --git a/Gemfile b/Gemfile
index 63b67ff2..a87314a6 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,5 +1,5 @@
 source 'https://rubygems.org'
-ruby '3.3.4'
+ruby '3.3.5'
 
 gem 'rails', '~> 7.1', '>= 7.1.3.4'
 
diff --git a/deploy/deploy.yml b/deploy/deploy.yml
index 5e878296..3ce6aebb 100644
--- a/deploy/deploy.yml
+++ b/deploy/deploy.yml
@@ -6,6 +6,8 @@
   vars:
     local_app_root: "{{ playbook_dir  }}/.."
     remote_project_root: "/srv/impress"
+    ruby_version: "3.3.5"
+
     # deploy:setup should have added us to the "impress-deployers" group, so we
     # should be able to become the "impress" user without a password.
     ansible_become_password: ""
@@ -60,7 +62,7 @@
     - name: Configure Bundler to run in deployment mode
       command:
         chdir: "{{ remote_app_root }}"
-        cmd: /opt/ruby-3.3.4/bin/bundle config set --local deployment true
+        cmd: /opt/ruby-{{ ruby_version }}/bin/bundle config set --local deployment true
 
     # This ensures that, while attempting our current deploy, we don't
     # accidentally delete gems out from under the currently-running version.
@@ -70,7 +72,7 @@
     - name: Configure Bundler to *not* clean up old gems when installing
       command:
         chdir: "{{ remote_app_root }}"
-        cmd: /opt/ruby-3.3.4/bin/bundle config set --local clean false
+        cmd: /opt/ruby-{{ ruby_version }}/bin/bundle config set --local clean false
 
     # NOTE: Bundler recommends this, and they're pretty smart about it: if the
     # Gemfile changes, this shouldn't disrupt the currently-running version,
@@ -79,7 +81,7 @@
     - name: Configure Bundler to use the bundle folder shared by all app versions
       command:
         chdir: "{{ remote_app_root }}"
-        cmd: "/opt/ruby-3.3.4/bin/bundle config set --local path {{ remote_project_root}}/shared/bundle"
+        cmd: "/opt/ruby-{{ ruby_version }}/bin/bundle config set --local path {{ remote_project_root}}/shared/bundle"
 
     - name: Run `bundle install` to install dependencies in remote folder
       command:
@@ -87,7 +89,7 @@
         # The `--local` flag instructs Bundler to use the cached dependencies
         # in `vendor/cache`, instead of reading from the web, which is much
         # faster and more reliable!
-        cmd: /opt/ruby-3.3.4/bin/bundle install --local
+        cmd: /opt/ruby-{{ ruby_version }}/bin/bundle install --local
 
     - name: Update the `current` folder to point to the new version
       file:
@@ -111,7 +113,7 @@
     - name: Clean up gems no longer used in the current app version
       command:
         chdir: "{{ remote_app_root }}"
-        cmd: /opt/ruby-3.3.4/bin/bundle clean
+        cmd: /opt/ruby-{{ ruby_version }}/bin/bundle clean
       when: not skip_set_as_current
 
     - name: Find older app versions to clean up
diff --git a/deploy/files/impress.service b/deploy/files/impress.service.j2
similarity index 94%
rename from deploy/files/impress.service
rename to deploy/files/impress.service.j2
index 6ca8a1fa..a4917ff8 100644
--- a/deploy/files/impress.service
+++ b/deploy/files/impress.service.j2
@@ -5,7 +5,7 @@ Description=Dress to Impress webapp
 User=impress
 Restart=always
 WorkingDirectory=/srv/impress/current
-ExecStart=/opt/ruby-3.3.4/bin/bundle exec falcon host
+ExecStart=/opt/ruby-{{ ruby_version }}/bin/bundle exec falcon host
 Environment="RAILS_ENV=production"
 ; Set EXECJS_RUNTIME to save us from needing to install Node
 Environment="EXECJS_RUNTIME=Disabled"
@@ -35,4 +35,4 @@ NoNewPrivileges=true
 CapabilityBoundingSet=~CAP_SYS_ADMIN
 
 [Install]
-WantedBy=multi-user.target
\ No newline at end of file
+WantedBy=multi-user.target
diff --git a/deploy/setup.yml b/deploy/setup.yml
index ddeed66b..83e92d4b 100644
--- a/deploy/setup.yml
+++ b/deploy/setup.yml
@@ -6,6 +6,7 @@
   vars:
     email_address: "emi@matchu.dev" # TODO: Extract this to personal config?
     impress_hostname: impress.openneo.net
+    ruby_version: "3.3.5"
   vars_files:
     # mysql_root_password, mysql_user_password, mysql_user_password_2020,
     # dev_ips
@@ -170,21 +171,21 @@
       git:
         repo: https://github.com/rbenv/ruby-build.git
         dest: /opt/ruby-build
-        version: d22fa95a6e4c77945304c16ebe0d9513fec98cfb
+        version: v20240917
 
-    - name: Check if Ruby 3.3.4 is already installed
+    - name: Check if Ruby {{ ruby_version }} is already installed
       stat:
-        path: /opt/ruby-3.3.4
+        path: /opt/ruby-{{ ruby_version }}
       register: ruby_dir
 
-    - name: Install Ruby 3.3.4
-      command: "/opt/ruby-build/bin/ruby-build 3.3.4 /opt/ruby-3.3.4"
+    - name: Install Ruby {{ ruby_version }}
+      command: "/opt/ruby-build/bin/ruby-build {{ ruby_version }} /opt/ruby-{{ ruby_version }}"
       when: not ruby_dir.stat.exists
 
-    - name: Add Ruby 3.3.4 to the global PATH, for developer convenience
+    - name: Add Ruby {{ ruby_version }} to the global PATH, for developer convenience
       copy:
         dest: /etc/profile.d/ruby_path.sh
-        content: PATH="/opt/ruby-3.3.4/bin:$PATH"
+        content: PATH="/opt/ruby-{{ ruby_version }}/bin:$PATH"
 
     - name: Install system dependencies for impress's Ruby gems
       apt:
@@ -248,14 +249,14 @@
       become_user: impress
       command:
         chdir: /srv/impress/versions/initial-placeholder
-        cmd: /opt/ruby-3.3.4/bin/bundle config set --local deployment true
+        cmd: /opt/ruby-{{ ruby_version }}/bin/bundle config set --local deployment true
       when: not current_app_version.stat.exists
 
     - name: Install the placeholder app's dependencies
       become_user: impress
       command:
         chdir: /srv/impress/versions/initial-placeholder
-        cmd: /opt/ruby-3.3.4/bin/bundle install
+        cmd: /opt/ruby-{{ ruby_version }}/bin/bundle install
       when: not current_app_version.stat.exists
 
     - name: Set the placeholder app as the current version
@@ -287,8 +288,8 @@
         state: directory
 
     - name: Create service file for impress
-      copy:
-        src: files/impress.service
+      template:
+        src: files/impress.service.j2
         dest: /etc/systemd/system/impress.service
       notify:
         - Reload systemctl