UE 4.26.2 hoses packaging of Windows projects...revert to previous version? How?

The recent 4.26.2 update hosed all my packaging attempts on several Windows projects. Everything was working fine on 4.26.1 and I’ve tried on 2 systems with same projects as well as older versions of the projects and backups…all fail to compile.
I simply want to revert to 4.26.1 but can find nothing on Epic’s site dealing with this.
Anybody have an idea how this can be done?
Thanx
MT