One of the biggest issues of upgrading an estate to a newer version of SEP is the issue with support teams keeping local copies of older packages that they use to create new builds. So even when you are pushing out auto upgrades you still see machines appearing on the network with older versions. An even sending out constant emails to tell support teams there is a newer version usually falls on deaf ears so you are spending an endless ammount of time trying to get networks and SEP clients upgraded or rebooted to upgrade.
It would be useful if there was an ability to set an expiry time on a package, so for example you make a package evailable on a share for support teams with say a week expiry on it the support teams can use that for a week then after that week the client will refuse to install notifying the team to download another package from the share. In the mean time the SEPM deletes the old package and refreshes them in the share for another week or longer.
Or possibly the ability to block older clients when they report into the SEPM to notify support teams instantly that this is an old version and they need to install or upgrade to the newer version of SEP client available.
I know host integrity policy can be configured to do this but then the policy needs updating everytime there is a release and over multiple SEPMs can be quite a large task.