Quote from Edit Name :

I used modo from 601 to 801. I stayed on 801 for a few years because upgrading to future releases meant being tied to either subscriptions or maintenance commitments. It's not an appealing option if I decide the latest release wasn't worth upgrading.

If there's an upgrade path with huge promotion from modo 801 to 17 I would consider it for old times sake.
I now use blender but I miss modo's modelling workflow.

It appears that anyone can download the license and current version of modo - though I am not sure the Foundry has said that so it may be like the "free" Adobe apps when they made versions that didn't require activation following the failure of their servers for CS2 but they were intended only for those with a real license.