I'm posting this here not because GMS is at fault, but is the critical factor.

We continue to use GroupWise 2014R2 as our email system and also use GMS 2014.
We currently have 70+ Blackberry devices, which uses BES 12.5 for routing messages and enforcing handset polices.
As BES 12.5 can sync email with Active Sync, we use GMS to sync emails between BES and GroupWise Post offices.

Blackberry has stopped production of Blackberry handsets, also we have been informed that UEM the product which supersedes BES, cannot be used between GMS and IOS devices.

We need to swap to another handset provider and management system, but we need to be able to lock down policies AND also work with GroupWise/GMS.

It seems there are many Mobile management solutions, but we need one tried and tested to work with the existing GroupWise structure.

If not, we face the prospect of migrating to EX*******, (sorry for almost saying the E word)