Migrate Availability Groups from SQL Server 2014 to 2016 Is it possible to migrate AGs 2014 to 2016?
We are currently on 2014.

Or we need to rebuild from scratch on 2016 with old backup files.

Anyone who have done it please suggest the pros and cons .

What things to consider for this change .
Yes it is possible and you do not need to rebuild from scratch.

This is well documented here and you can follow the steps and best practices from this document.

Upgrading Always On Availability Group Replica Instances

To check all versions that qualify for rolling upgrade see this document.

Supported Version and Edition Upgrades

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