To help troubleshoot, confirm for me the version of the mod on your system. Go to:
(if you have multiple steam library locations it'll be at the same one as your RimWorld install)
Right click the file "HaulToStack.dll" and let me know what the "File Version" says under the "Details" tab.

It should say 1.4.1.0 If it doesn't please unsubscribe to the mod, resubscribe and confirm it says 1.4.1.0
Once we've confirmed your mod is properly updated and shows 1.4.1.0, check if you still get the error and we'll go from there.

Thanks @itsComcastic.

Ignore my earlier comments I provided the wrong link, I checked the version of the files and confirmed I was on v1.0.0.0. Unsubcribing didn't get rid of the files or update them on resubscription. But deleting them manually, and then resubscribing did the trick. Thank you.

Awesome, Glad to hear that worked.

hmm deleted files manually , unsubscribed , resubscribed still says 1.0.0.0 in my details tab.

I just did some searches.. Saw someone recommends unsubscribing then resubscribing while in game from the game ui:
source: https://steamhost.cn/steamcommunity_com/app/294100/discussions/0/3058492678368549359/

Another post suggests trying verifying file integrity for the game
source: https://old.reddit.com/r/RimWorld/comments/oreg12/forcing_steam_mods_to_update/

If neither of these options works for you, you can also try replacing the contents of the 949498803 folder with the contents of my zip on github.. or install extract the zip to the rimworld mods folder
https://github.com/jkluch/HaulToStack/releases/tag/v1.4.1