Moving back up from one device to another

Hi All.
I have inherited a customer running an RB532A. They were having some issues and I found they were still on RouterOS 2.9.17. I have updated them to the latest RouterOS version, not without having to buy a new license key because even though I followed the suggestions people left on the forum about updating router OS, as soon as I installed RouterOS 3.30 it screwed it up and I had to go back to version 3.25, but the license was gone and the only way, after many hours of trying, to fix it was to buy a new license…then it was fine!
However, they still have the odd issue and I am thinking of upgrading them to an RB751U. Before I did anything, I took a back up of the original install - a life saver in the end :slight_smile: So, can I apply that backup (from the RB523A) to an RB751? I assume there will be the odd thing I need to change, but is this a good approach?
Appreciate any suggestions.

Jeremy

You cannot apply backup to other ros version or device type. There is no problem to run. 6.30.1 on rb532, you just need to upgrade license during upgrading process somewhere between ros 3.x and 4.x. There is correct procedure somewhere so use google first… If you downgrade by netinstall to old version the router will work again so you can upgrade step by step again including license upgrade.