Following the announcement of Visual Studio for Mac’s retirement, for the next 65 hours we are offering a 65% discount on new subscriptions for Rider, the only cross-platform .NET IDE.
The offer is valid for a new one-year personal subscription purchased before 6:00 am UTC, September 4, 2023.
Yes, included in the 12 month license is the entitlement to that version forever.
https://sales.jetbrains.com/hc/en-gb/articles/207240845-What-is-perpetual-fallback-license-
Also worth noting that unlike every other subscription service they reward loyalty with large discounts on renewing annually.