Fzf.kak stops working after updating to tmux 3.4

Hi, I’ve run into a weird issue.

After updating my (NixOS) system, it seems like the plugin fzf.kak has stopped working. When running any of its commands, there is no fzf split appearing. I only see the clippy popup with the help for the keyboard bindings. The *debug* buffer doesn’t show any related information.

Any ideas for how to debug this? Not much to go on, I know…

My fzf.kak configuration is pretty minimal:

plug "andreyorst/fzf.kak" config %{
  map global user f ": fzf-mode<ret>" -docstring "fzf"

In the command line, fzf seems to work fine still…

I already tried deleting my ~/.config/kak/plugins directory and recreate it using :plug-install, but it didn’t do any difference.

I think I narrowed this down to tmux having been updated from version 3.3a to 3.4. I don’t know why that is a problem though.

get tmux server and client logs