How can I migrate SFB 2015 to 2019 in Windows server 2019
You shoud first upgrade your Windows server from 2012 to 2019 firstly, then you could follow these steps to migrate Skype for Business 2015 to Skype for Business 2019:
Phase 1: Plan your migration
Phase 2: Prepare for migration
Phase 3: Deploy Skype for Business Server 2019 pilot pool
Phase 4: Move test users to the pilot pool
Phase 5: Add Skype for Business Server 2019 Edge Server to pilot pool
Phase 6: Move from pilot deployment into production
Phase 7: Complete post-migration tasks
Phase 8: Decommission legacy pools
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