The patch was intended to fix bugs such as stats not updating and incorrect rankings however it seems the patch actually just corrupts the game for those who downloaded the game in Europe.

When starting Warhawk you get prompted to install the new patch. Once the patch is installed you get sent back to the XMB. Starting Warhawk agian results in an error message:
'This content cannot be accessed on your account'
It seems the patch deletes your authentication name. Meaning that the game no longer recognises you as the owner and therefor won't let you start Warhawk.
However it seems this only effect European players and also only those that downloaded the game from the PS Store.

Thankfully developer Dylan Jobe was quick to respond and it seems the only solution to this is to re-download the game from the store and delete the old corrupted version of Warhawk.

This is not good for Incognito. Not everyone with Warhawk reads online forums. Many will never know that they need to download the game again and they will probably be really angry that the money they spent on Warhawk is wasted.