diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 15c5779..1dfda55 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -12,7 +12,6 @@ jobs:
           - '3.2'
           - '3.3'
         gemfile:
-          - gemfiles/Gemfile.rails61
           - gemfiles/Gemfile.rails70
           - gemfiles/Gemfile.rails71
           - gemfiles/Gemfile.rails72
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5efd83a..a47295e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,13 @@
 ## [Unreleased]
 ### Fixed
 * Capistrano: Add missing `tmpdir` requirement to deploy application secrets
+* Capistrano: cap deploy:setup should be safe on existing deployments
+
+### Added
+* Capistrano: add task deploy:preinstall to preinstall ruby and bundled gems
+
+## Changed
+* Drop support for Rails 6.1
 
 ## 7.3.1 / 2025-01-02
 ### Added
diff --git a/config/rubocop/ndr.yml b/config/rubocop/ndr.yml
index 853f50a..e843553 100644
--- a/config/rubocop/ndr.yml
+++ b/config/rubocop/ndr.yml
@@ -4,7 +4,7 @@
 #
 # See the README for instructions on using in a project.
 
-require:
+plugins:
   - rubocop-rails
   - rubocop-rake
 
diff --git a/gemfiles/Gemfile.rails61 b/gemfiles/Gemfile.rails61
deleted file mode 100644
index 6083b3b..0000000
--- a/gemfiles/Gemfile.rails61
+++ /dev/null
@@ -1,7 +0,0 @@
-source 'https://rubygems.org'
-gemspec path: '..'
-
-gem 'activesupport', '~> 6.1.0'
-
-# Latest concurrent-ruby breaks Rails < 7.1. See https://github.com/rails/rails/issues/54260
-gem 'concurrent-ruby', '1.3.4'
diff --git a/lib/ndr_dev_support/capistrano/ndr_model.rb b/lib/ndr_dev_support/capistrano/ndr_model.rb
index e423af9..b229a01 100644
--- a/lib/ndr_dev_support/capistrano/ndr_model.rb
+++ b/lib/ndr_dev_support/capistrano/ndr_model.rb
@@ -4,6 +4,7 @@
 require_relative 'assets'
 require_relative 'deploy_secrets'
 require_relative 'install_ruby'
+require_relative 'preinstall'
 require_relative 'restart'
 require_relative 'revision_logger'
 require_relative 'ruby_version'
@@ -53,11 +54,15 @@
       # sticky; all deployments made within it should be owned by the deployer group too. This
       # means that e.g. a deployment by "bob.smith" can then be rolled back by "tom.jones".
       run "mkdir -p #{deploy_to}"
-      run "chgrp -R deployer #{deploy_to}"
+      # Set deployer group for everything created by this user
+      # run "chgrp -R deployer #{deploy_to}"
+      run "find #{deploy_to} -group #{fetch(:user)} -print0 |xargs -r0 chgrp -h deployer"
 
       # The sticky group will apply automatically to new subdirectories, but
       # any existing subdirectories will need it manually applying via `-R`.
-      run "chmod -R g+s #{deploy_to}"
+      # run "chmod -R g+s #{deploy_to}"
+      run "find #{deploy_to} -user #{fetch(:user)} -type d " \
+          '-not -perm -2000 -print0 |xargs -r0 chmod g+s'
     end
 
     desc 'Custom tasks to be run once, after the initial `cap setup`'
@@ -67,8 +72,12 @@
         run "mkdir -p #{full_path}"
 
         # Allow the application to write into here:
-        run "chgrp -R #{application_group} #{full_path}"
-        run "chmod -R g+s #{full_path}"
+        # run "chgrp -R #{application_group} #{full_path}"
+        # run "chmod -R g+s #{full_path}"
+        run "find #{full_path} -user #{fetch(:user)} -not -group #{application_group} " \
+            "-print0 |xargs -r0 chgrp -h #{application_group}"
+        run "find #{full_path} -user #{fetch(:user)} -type d " \
+            '-not -perm -2000 -print0 |xargs -r0 chmod g+s'
       end
 
       fetch(:shared_paths, []).each do |path|
@@ -185,6 +194,14 @@ def target_ruby_version_for(env)
   match ? match[:version] : raise('Unrecognized Ruby version!')
 end
 
+def log_deployment_message(msg)
+  name = fetch(:deployer_name, capture('id -un').chomp)
+  log  = File.join(shared_path, 'revisions.log')
+  msg  = "[#{Time.now}] #{name} #{msg}" # rubocop:disable Rails/TimeZone
+
+  run "(test -e #{log} || (touch #{log} && chmod 664 #{log})) && echo #{Shellwords.escape(msg)} >> #{log};"
+end
+
 def add_target(env, name, app, port, app_user, is_web_server)
   desc "Deploy to #{env} service #{app_user || 'you'}@#{app}:#{port}"
   task(name) do
diff --git a/lib/ndr_dev_support/capistrano/preinstall.rb b/lib/ndr_dev_support/capistrano/preinstall.rb
new file mode 100644
index 0000000..f71c995
--- /dev/null
+++ b/lib/ndr_dev_support/capistrano/preinstall.rb
@@ -0,0 +1,37 @@
+Capistrano::Configuration.instance(:must_exist).load do
+  namespace :deploy do
+    desc <<~DESC
+      Preinstall ruby and gems, then abort and rollback cleanly, leaving the
+      current installation unchanged.
+
+      This is particularly useful for ruby version bumps: installing the new
+      ruby version and all the bundled gems can take a long time.
+
+      This aborts before updating out-of-bundle gems, in case that causes
+      issues when restarting the currently installed version.
+
+      Usage:
+        cap target deploy:preinstall
+    DESC
+    task :preinstall do
+      # Running this task sets a flag, to make ndr_dev_support:check_preinstall abort.
+      # We do this in a roundabout way on Capistrano 2, because deploy:update_code
+      # explicitly runs deploy:finalize_update, instead of using task dependencies.
+      set :preinstall, true
+    end
+  end
+
+  namespace :ndr_dev_support do
+    desc 'Hook to abort capistrano installation early after preinstalling ruby and in-bundle gems'
+    task :check_preinstall do
+      next unless fetch(:preinstall, false)
+
+      log_deployment_message("preinstalled #{real_revision}")
+      warn Rainbow("Successful preinstall for target: #{fetch(:name)}")
+      abort 'Aborting after successful preinstall'
+    end
+  end
+
+  after 'deploy:preinstall', 'deploy:update'
+  before 'ndr_dev_support:update_out_of_bundle_gems', 'ndr_dev_support:check_preinstall'
+end
diff --git a/lib/ndr_dev_support/capistrano/revision_logger.rb b/lib/ndr_dev_support/capistrano/revision_logger.rb
index 97af468..8178b74 100644
--- a/lib/ndr_dev_support/capistrano/revision_logger.rb
+++ b/lib/ndr_dev_support/capistrano/revision_logger.rb
@@ -2,11 +2,7 @@
   namespace :ndr_dev_support do
     desc 'Append to the log of deployments the user and revision.'
     task :log_deployment, except: { no_release: true } do
-      name = fetch(:deployer_name, capture('id -un'))
-      log  = File.join(shared_path, 'revisions.log')
-      msg  = "[#{Time.now}] #{name} deployed #{latest_revision}"
-
-      run "(test -e #{log} || (touch #{log} && chmod 664 #{log})) && echo #{msg} >> #{log};"
+      log_deployment_message("deployed #{latest_revision}")
     end
   end