let's be patient or use this neat trick if you really cant play without the trainer (no judgement here)MrAntiFun:
it was a big update , 6.7GB so it will take a bit of time to update .
If you don't mind playing without the new patch, you can do the following to revert back to a version that works with the trainer:
1) Right-click the game in your Steam library and select "Properties"
2) Select the "Betas" tab
3) Use the drop-down box to opt-in to the "public_beta"
After that the game will revert back to the last version which does work with the latest trainer.