In the process of upgrading CA Gen from 8.0 to 8.6, as part of the prerequisite tasks, we are trying to check-in all subsets for all models in our CA Gen Host Encyclopedia.
Is there any way to check-in or override checkout for all checked out subsets in a model without having to process each checked out subset one at a time?

Release : Upgrade to Gen 8.6
Component : CA Gen Host Encyclopedia

On the Gen Host Encyclopedia (HE) there is no feature available that will do a mass check in or override check out because models and subsets checked out can be associated to many different user ids.

Either upgrading a Gen HE 8.0 to 8.6 in-place or creating a new Gen 8.6 HE with new DB using the DB2 Unload/Load utility is the optimum way to preserve all existing HE data. The other option for new Gen 8.6 HE creation is to copy the models (download/upload one model at a time) from the old HE to the new HE, but that option does not preserve subset definitions, user access, aggregate sets, and ancestry data. More information can be found here: 

CA GEN 8.6 > Installing > Upgrading to a New Release

CA GEN 8.6 > Installing > Install CA Gen on z/OS > Preparing to Start Host Encyclopedia > Populate a Host Encyclopedia

CA GEN 8.6 > Installing > Install CA Gen on z/OS > Preparing to Start Host Encyclopedia > Copy Models to a Host Encyclopedia

We do recommend to check in of all models & subsets before an upgrade to avoid the possibility of losing any changes that have not not been updated to the HE from the Workstation Toolsets. However for this upgrade where the Encyclopedia schema does not change across 8.0 -> 8.6 ('9.2.A6') using either HE upgrade in-place or new HE/DB with DB2 Unload/Load utility should in theory not encounter any problems because in both cases they would retain the same object ids & check out information and there is no change to Prior schema and second prior schema support. However if you will be populating the new HE using the copy model approach then check in of all models & subsets is mandatory.