Buckle up people who want long war compatibility, there is a way to get the same effect.

Preface: if at any point you get confused, stop what you are doing or you will have to reinstal the mod. Also, backup your files. And you don't actualy need this mod, I'm posting this here because this would probably be the first place people look.

Now on to the edits you need to do. First things first, grab yourselves notepad++

Then you go to \SteamApps\workshop\content\268500\844674609\Config to find your long war files. Next, I went through and edited 2 files:XComLW_Overhaul.ini and XComGameData_WeaponData.ini, those are the 2 files you will be editing with Notepad++ (rightclick them and you should see the option to edit with notepad++, otherwise just use open with)

In Overhaul, look for line 357 to find where the weapon templates begin and there go on ahead and edit the "Slots=3" entry on weapons to whatever value you want it to have. I recomend a max of 6. I also recomend you only edit slot values for weapons that already have slots, so leave the pistol and other weapons untouched, until grimy's loot mod can be made compatible with long war, you will have nothing to put in those slots anyway and you might cause a crash.

Now, I'm not exactly sure if this is needed or not, but I did it anyway (I advise you skip this and tell me if it works with just the editing of Overhaul.ini): go to WeaponData and look through it for the templates of each weapon class (in the case of long war, 3 sections: Basic weapons (it has the conventional magnetic and Beam tear under it), Laser and Coil) and there, for each weapon type (AssaultRifle, Shotgun, LMG, SMG and Sniper Rifle) go ahead and follow each entry of *weapontype*_*weapontier*_iEnvironmentDamage (ex for plasma assault rifle of the entry in question: AssaultRifle_Beam_iEnvironmentDamage, replace the first 2 sections with what you need) with an entry of *weapontype*_*weapontier*_iUpgradeSlots = the same number you used in the Overhaul file (so if in overhaul you used 6, use 6 here as well). Do this again for every weapon type in every weapon tier. Coil weapon tier uses Cannon instead of LMG btw, keep this is mind if you don't find LMG_Coil_*stat*.

Small note: respect the structure of the section you are editing. In the Basic Weapon Templates, each stat is given in a block of 3 for the 3 basic tiers, do the same here. After the block of 3 iEnviromentDamage entries leave an empty line and type your block of iUpgradeSlots entries. Keeps the file clean and easy to find any mystakes if you make any.

And congrats, you have 6 upgrade slots per weapon. Do note however that if Long war 2 updates any of the 2 ini files above, you will have to re-do the edits BEFORE you try to load that savegame. That's the unfortunate limit of this method. If anyone wants to make a mod to overwrite LW in this aspect, he is welcome to do it based on what I described here.

Another note: theoreticaly, you can use Overhaul.ini to give upgrade slots to any weapon in the game. I advise you to be carefull if you choose to play around with that. And always keep backups handy.