Hi,
BLT 2 changed a bunch of stuff, and you might need to update your mod if it doesn't work anymore.

New mod.txt keys

There is new keys for the mod.txt file:

"blt_version" : 2,                // This key is now needed if you want to get rid of the red text "this mod is outdated"
"image" : "blt.png",              // Used if you want to add an icon to your mod.
"color" : "255 0 255",            // This will determine the color of your mod box in the mod manager.
"undisablable" : true,            // Setting to true will prevent players to disable your mod
"disable_safe_mode" : false,      // Not sure what is safe mode. Leave it to false i guess

Mod options node changed

If your mod used options, you will need to change the parent_menu_id from lua_mod_options_menu to blt_options

New BLT functions

The doc hasn't been updated so you can always check what changed in the BLT github: https://github.com/JamesWilko/Payday-2-BLT-Lua