Upgrade from Afaria7 SP4 HF09

Hi

We are currently on Afaria 7 SP4 HF09, and to support the new ios 9 devices we either need to update our current environment to Afaria 7 SP4 HF19 or Afaria 7 SP5 HF13.

So the questions is which one would be the best option. Installing a hotfix 19 or upgrading the environment to SP5 HF13.

Please suggest some documents to go through for both the options.

Currently I am checking the below link for the upgrade to SP5.

http://help.sap.com/Download/Multimedia/zip-afaria/SP5_Upgrading.pdf    

Thanks

RR