11.2 HF1 or 11.1 HF5 ?

Minor release numbers are used as follows;

 

 

Minor (point release) version numbers (x.2) are numbered as follows;

 

•Even numbered – feature releases; you would generally only use this if it included a feature that you required.

 

•Odd number – maintenance release; likely more stable than a feature release and will include bug fixes and security enhancements.

 

 

But of course, it's never that clear cut and I'd advice you to follow nitass's advice.