I have the same Problem with 3 PE R520. They're running Windows Server 2012R2 and Windows Server 2008R2. A link the Firmware 21.3.1-0001 or higher would be nice. Edit: Just found it. 
Hello, OMSA is showing that the RAID Firmware is outdated on the PE R420. I checked on the drivers page but there isn't a firmware package listed for PERC H710 Mini. Is there one that I am not able to download for some reason? Thanks,Vamsi
PE R420 PERC H710 Mini