When your license is perpetual, it means that your license does not expire. That is, the license will not stop working on a predetermined date and time.
The software should continue to function without intervention on the same machine with the same operating system on which it was originally installed. However, we cannot guarantee compatibility of the software with future computers or operating systems, or that our own internal systems won't eventually evolve to the point where we are no longer able to support re-installations, or that we will be able to provide support.
Please note that the license being "perpetual" applies to a specific version (e.g. Maple or MapleSim 2019), and that the license applies to all updates to that same version (e.g. Maple or MapleSim 2019.3), but not future versions (e.g. Maple or MapleSim 2020).