It seems tmux has deprecated split-window -p<value> in favor of split-window -l<value>% in 3.1, fully removing support for split-window -p<value> in 3.4:
CHANGES FROM 3.0a TO 3.1
* Add support for percentage sizes for resize-pane ("-x 10%"). Also change
split-window and join-pane -l to accept similar percentages and deprecate the
-p flag.
This adds a tmux version check, after which split-window calls constructed by tmex will use -l<value>% if current version is >=3.1, and continue using -p<value> if version is <3.1. If tmux version cannot be determined, a warning will be emitted and tmex will continue to use the old -p flag.
Fix for https://github.com/evnp/tmex/issues/7 (thanks @liangkarl!)
It seems tmux has deprecated
split-window -p<value>in favor ofsplit-window -l<value>%in 3.1, fully removing support forsplit-window -p<value>in 3.4:https://github.com/tmux/tmux/blob/master/CHANGES#L663
This adds a tmux version check, after which
split-windowcalls constructed by tmex will use-l<value>%if current version is >=3.1, and continue using-p<value>if version is <3.1. If tmux version cannot be determined, a warning will be emitted and tmex will continue to use the old-pflag.