As you can see, you don’t need a subscription to use Simbrief. With all its features and default data, Simbrief is free, and you currently have access to support.
What you can do is, subscribe for one month only - bring all your systems (Simbrief, sim, and all your addons) on the same AIRAC cycle level, and that’s it.
We don’t remove the data on your system (also not in Simbrief), so you can use the cycle (even outdated ones) as long as you do not initialize/re-install your OS or your SIM. With this workaround, you have a consistent system in place.
Hope that helps
Richard