XCompose not taken into account?

Since I upgraded NixOs, my .XCompose is not taken into account anymore. I use ibus (bépo AFNOR input method), and it used to work perfectly fine before the upgrade. I’m using this ~/.XCompose file: https://raw.githubusercontent.com/andrewathalye/bepo-xcompose-fix/main/XCompose and now when I type: AltGr-T (bépo), I get:


instead of the usual .

I’m using:

  i18n.inputMethod = {
    enabled = "ibus";
    ibus.engines = with pkgs.ibus-engines; [ table table-others ];

  # Enable the KDE Desktop Environment.
  services.xserver.displayManager.sddm.enable = true;
  services.xserver.desktopManager.plasma5.enable = true;

and then configured bépo AFNOR (needed for math) in the IBUS preferences program. Any idea how to debug this?