diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e4fa1e801..839bc4e65 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: ${{ startsWith(matrix.ruby-version, '3.4.') && '--enable=frozen-string-literal' || '' }}
diff --git a/lib/kamal/commands/base.rb b/lib/kamal/commands/base.rb
index 7521780ad..c0eac91cc 100644
--- a/lib/kamal/commands/base.rb
+++ b/lib/kamal/commands/base.rb
@@ -11,14 +11,7 @@ def initialize(config)
     end
 
     def run_over_ssh(*command, host:)
-      "ssh".tap do |cmd|
-        if config.ssh.proxy && config.ssh.proxy.is_a?(Net::SSH::Proxy::Jump)
-          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}'"
-        end
-        cmd << " -t #{config.ssh.user}@#{host} -p #{config.ssh.port} '#{command.join(" ").gsub("'", "'\\\\''")}'"
-      end
+      "ssh#{ssh_proxy_args} -t #{config.ssh.user}@#{host} -p #{config.ssh.port} '#{command.join(" ").gsub("'", "'\\\\''")}'"
     end
 
     def container_id_for(container_name:, only_running: false)
@@ -92,5 +85,14 @@ def grep(*args)
       def tags(**details)
         Kamal::Tags.from_config(config, **details)
       end
+
+      def ssh_proxy_args
+        case config.ssh.proxy
+        when Net::SSH::Proxy::Jump
+          " -J #{config.ssh.proxy.jump_proxies}"
+        when Net::SSH::Proxy::Command
+          " -o ProxyCommand='#{config.ssh.proxy.command_line_template}'"
+        end
+      end
   end
 end