McAfee Free Antivirus won't update from Play Store returning error -505 I am putting McAfee in System/app directory to prevent standard users from uninstalling it.

Once I try to update the package from Play Store, the download progress reaches 100% and when it tries to replace the old package I am getting Error -505

After a searching, it looks like Android Lollipop have an issue with Adobe Air application, but FYI this is Lollipop 5.1

This is what i am getting from bug repport: different signatures ?? any ideas??

Session 1987113136:
  userId=0 installerPackageName=com.android.vending installerUid=10018 createdMillis=1437157124890 
  stageDir=/data/app/vmdl1987113136.tmp stageCid=null 
  mode=1 installFlags=0x12 installLocation=1 sizeBytes=10749412 appPackageName=com.wsandroid.suite appIcon=false 
  appLabel=Security &amp; Antivirus -FREE originatingUri=null referrerUri=null abiOverride=null 
  mClientProgress=1.0 mProgress=0.90000004 mSealed=true mPermissionsAccepted=true mDestroyed=true mBridges=1 
  mFinalStatus=-7 
  mFinalMessage=Package com.wsandroid.suite signatures do not match the previously installed version; ignoring!`
The app with this package name: com.wsandroid.suite was not signed by the same certificate as the one from the Play store.  This is a fundamental security requirement.  You will have to make sure the app you are installing originally is signed with the same key as the one in the Play store.

There is no way to get around this security requirement (matching signatures) to the best of my knowledge.