diff --git a/tmux.conf b/tmux.conf
index bb4b1a1..9af16ed 100644
--- a/tmux.conf
+++ b/tmux.conf
@@ -38,6 +38,14 @@ set -as terminal-features ',xterm*:clipboard'
 # Focus events enabled for terminals that support them
 set -g focus-events on
 
+# Forward modifier information so apps, csi-u format requires tmux 3.5+.
+if -b '~/.config/tmux/check-version.sh ">= 3.2"' {
+  set -g extended-keys on
+}
+if -b '~/.config/tmux/check-version.sh ">= 3.5"' {
+  set -g extended-keys-format csi-u
+}
+
 # Aggressively resize the chosen window to smallest/largest session
 setw -g aggressive-resize on