diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e4fa1e801..187cb4753 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -27,6 +27,7 @@ jobs:
           - "3.1"
           - "3.2"
           - "3.3"
+          - "3.4.0-preview2"
         gemfile:
           - Gemfile
           - gemfiles/rails_edge.gemfile
@@ -41,6 +42,9 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      - name: Remove gemfile.lock
+        run: rm Gemfile.lock
+
       - name: Install Ruby
         uses: ruby/setup-ruby@v1
         with:
@@ -49,3 +53,5 @@ jobs:
 
       - name: Run tests
         run: bin/test
+        env:
+          RUBYOPT: ${{ matrix.ruby-version == '3.4.0-preview2' && '--enable=frozen-string-literal' || '' }}
diff --git a/lib/kamal/commands/base.rb b/lib/kamal/commands/base.rb
index 7521780ad..94a04a39c 100644
--- a/lib/kamal/commands/base.rb
+++ b/lib/kamal/commands/base.rb
@@ -11,13 +11,13 @@ def initialize(config)
     end
 
     def run_over_ssh(*command, host:)
-      "ssh".tap do |cmd|
+      "ssh".then do |cmd|
         if config.ssh.proxy && config.ssh.proxy.is_a?(Net::SSH::Proxy::Jump)
-          cmd << " -J #{config.ssh.proxy.jump_proxies}"
+          cmd = "#{cmd} -J #{config.ssh.proxy.jump_proxies}"
         elsif config.ssh.proxy && config.ssh.proxy.is_a?(Net::SSH::Proxy::Command)
-          cmd << " -o ProxyCommand='#{config.ssh.proxy.command_line_template}'"
+          cmd = "#{cmd} -o ProxyCommand='#{config.ssh.proxy.command_line_template}'"
         end
-        cmd << " -t #{config.ssh.user}@#{host} -p #{config.ssh.port} '#{command.join(" ").gsub("'", "'\\\\''")}'"
+        "#{cmd} -t #{config.ssh.user}@#{host} -p #{config.ssh.port} '#{command.join(" ").gsub("'", "'\\\\''")}'"
       end
     end