RouterOS upgrade capabilities are not limited by time, but by version, and this depends on the RouterOS license level. For example if you are running RouterOS v5, your license could restrict the upgrade only to v6, and not to v7. The following examples describe how this is determined:
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has been removed from the Manual:License wiki page. Is it correct that I can upgrade my RouterBoard to new versions as long as it runs or a version is shipped for the CPU architecture? Thx for you’re info.
Hmm.. also line “upgradable-to: XXX” has disappeared from license information (/system license print) . I have one ROS 6.17 (lev4 license) and there it still exist, but not anymore in ROS 6.20 (lev5)..
Yes. It was already written on the forum that the updates and upgrades will be unlimited till the end of the life of each device type. It means until the new versions will support your hardware, you can upgrade for free. But expect the problems like some mipsbe devices with 32MB ram are sometimes poorly running ros 6.x. And old 1xx devices are not supported by 6.x. So actually moving upgradable-to field forward or keeping support to old hw in new versions is one like other. No certainty anyway.