Do I need the 1.5 Kingdoms patch for installation?

I always thought that the vanilla M2TW Kingdomes needed to be patched to 1.5 but the installation guide does not specify this requirement anymore.

Is it now not required, ie just Kingdoms expansion will do?

Thanks

I play without patch and have no major problems.

Yes you do. You absolutely need the 1.5 patch for Kingdoms to play without any issues.