Quorum Queues are a superior replacement for Classic Mirrored Queues that were introduced in RabbitMQ version 3.8. And there are two complementary reasons why you would need to migrate.

First of all, Classic Mirrored Queues were deprecated in 3.9, with a formal announcement posted on August 21, 2021. They will be removed entirely in 4.0

But also they are more reliable and predictable, faster for most workloads and require less maintenance - so you shouldn’t feel that your hand is being forced without no apparent reason.

Quorum Queues are better in all regards, but they are not 100%-compatible feature-wise with Mirrored Queues. Thus the migration can look like a daunting task.

After a sneak peek into the future performance improvements, this post will outline a few possible migration strategies, including guidance on how to deal with all the incompatible features. Hopefully making migration process not so scary.