I am trying to upgrade the rabbitmq to the latest 3.12.12 version. currently I am in 3.11.0 version. As it is required to enable all feature flags from previous version, one feature flag is not present in 3.11.0 which is "classic_queue_type_delivery_support".
I tried enabling all the feature flag from the 3.11.0 version, but "classic_queue_type_delivery_support" flag is missing.
are you enabling 'classic_queue_type_delivery_support' before you upgrade? the feature came in 3.10.9 and should be present in 3.11.0... ref https://www.rabbitmq.com/feature-flags.html#list-of-feature-flags
several discussion of rabbitmq upgrade problems on RabbitMQs official Discord server. -might find a matching answer there also.
if you have not read the release-notes for 3.12.0 you might get som pointers there also: https://github.com/rabbitmq/rabbitmq-server/blob/main/release-notes/3.12.0.md#required-feature-flags