Upgrading RabbitMQ and Erlang - Ordering and errors after upgrading

[DMahoney0]

I have a machine that I've used WIX to install RabbitMQ 3.7.3 and Erlang 20.0 in the past. Now I want to upgrade to RabbitMQ 3.7.28 or later to get the patch fixes.

I've tried upgrading RabbitMQ to 3.7.28 first and then installing Erlang 21.3 according to the Compatibility Matrix and the upgrade instructions

Order of installation:

• Erlang 20.0 (in the past / previous release)
• RabbitMQ 3.7.3 (in the past / previous release)
• Upgrade to RabbitMQ 3.7.28 (today)
• Upgrade to Erlang 21.3 (today)

I've also tried upgrading to the latest RabbitMQ, 3.8.11, with Erlang 23.2.

Order of installation:

• Erlang 20.0 (in the past / previous release)
• RabbitMQ 3.7.3 (in the past / previous release)
• Upgrade to RabbitMQ 3.8.11 (today)
• Upgrade to Erlang 23.2 (today)

In both cases, I am getting a error when running the "rabbitmqctl.bat status" command after completely the upgrades:
`11:48:41.291 [error] Loading of c:/Program Files (x86)/RabbitMQ Server/rabbitmq_server-3.7.28/escript/rabbitmqctl/Elixir.RabbitMQCtl.beam failed: :badfile

11:48:41.295 [error] beam/beam_load.c(1862): Error loading module 'Elixir.RabbitMQCtl':
This BEAM file was compiled for a later version of the run-time system than 20.
To fix this, please recompile this module with an 20 compiler.
(Use of opcode 162; this emulator supports only up to 159.)

** (UndefinedFunctionError) function RabbitMQCtl.main/1 is undefined (module RabbitMQCtl is not available)
(rabbitmqctl) RabbitMQCtl.main(["status"])
(elixir) lib/kernel/cli.ex:105: anonymous fn/3 in Kernel.CLI.exec_fun/2`

Any help on how I can debug this or if I am doing something wrong with the ordering would be helpful!

[lukebakken]

You must uninstall the previous version of Erlang before installing a new Erlang and RabbitMQ version. This is due to the fact that the RabbitMQ .exe installer searches for the Erlang installation in a way that sometimes selects the old version as the one to use.

Please see the following documentation:

https://www.rabbitmq.com/install-windows.html#upgrading-erlang (Note: we need to add a caveat about uninstalling Erlang - rabbitmq/rabbitmq-website#1136)

https://www.rabbitmq.com/windows-quirks.html#multiple-erlang-versions

[DMahoney0]

@lukebakken do you know the command to uninstall the broker?

Taken from: "If you have an existing installation and are planning to upgrade the Erlang VM from a 32-bit to a 64-bit version then you must uninstall the broker before upgrading the VM. The installer will not be able to stop or remove a service that was installed with an Erlang VM of a different architecture."

I've tried "rabbitmq-service.bat stop" and then "rabbitmq-service.bat remove" but not getting far with that. Is there another uninstall command that you know of? Perhaps something with rabbitmqctl?

[lukebakken]

The .exe installer provides uninstall function. You should also be able to find an uninstall.exe file in the installation directory.