Minetest 5.4.0 was released February 23, 2021 and brings with it lots of new features and improvements. As a quick disclaimer this isn't an official video, I'm just a guy that enjoys Minetest and wants to share the news.
A few breaking changes.
The Use_texture_alpha field no longer takes a true/false boolean, but rather uses clip, blend, or opaque, check the documentation to see what you should be using.
Get_player_velocity and add_player_velocity were replaced with the shorter get_velocity and add_velocity. A quick search/replace in your code should take care of that.
Check out the video on Pick Pocket and the i3 mod.