Hi,
I have to administrate a Routerboard 532 with 2.9.30 installed and never touched since 4-5 years. I like to change different things and setup different services. I thought maybe it make sense to upgrade to the latest free availble version of RouterOS. Which is in my case 3.30.

software-id: "xxxxx"
upgradable-to: v3.x
nlevel: 4
features:

But I see a few risks:
- I did a backup of the configuration but I saw in the manual that the backup/restore functionality is difference between version 2.xx and 3.xx. So I maybe can't restore my config in the case that I have to reset all settings.
- I not found a download for 2.9.30 that I can go back in a emergency case

As a result I have a few questions:

- Make it sense to upgrade is there any benefit or security reason?
- Do you have a link for the download of 2.9.30?
- Is there any "BestPractice" guide availble how to upgrade or can I just updgrade from 2.xx to 3.xx without risk, can I use the backup configuration files as well for version 3.xx?

Thanks
Peter

No need to worry, Just do backup in case something will go wrong. Download ROS 3.30 and u're good to go (have same boards). After 3.30 u can upgrade 4.15 (Last stable ROS) and u should not lost any settings. Dont forget to update KEY before run 4.15 upgrade. Same with Bootloader (Latest for RB532 2.18)

Only to clear that I am not missunderstood you.

- I can use my backup from 2.9.30 to restore the configuration in 3.30?
- If I upgrade to version 4.15 I have to purchase the license key because I have actual version 2.xx and with "WISP AP (Level 4)" I can just upgrade to 3.xx for free, right? (Source: http://wiki.mikrotik.com/wiki/Manual:All_about_licenses)

Yes u will be able to use 2.9.30 backup in 3.30.
No u dont need to buy new key. Just after u will install 3.30 got to System>License and press Update License Key. After update bootloader Then u're good to go for 4.15 ROS

Ok upgrade from 2 to 3 worked well! Also Bootloader upgrade and license worked well.

But from 3.30 to 4.15 I have a little issue with the routing. Both Mikrotiks are bridged and the bridging works fine. On top is also a routing configured for the 192.168.1.x subnet from. But this not more work.

I like to go back until I understood the routing of both devices a bit better is a downgrade without risk possible?

Yes - Downgrade is possable by using /system package downgrade
I gues u need to select gateway in route list and thats all.

It was just the route backwards as you mentioned from one AP to the other.

Thanks for your help!

welcome..