I think the terminology used for the releases may be described as:
Stable Release: 2018.3 (currently at 2018.3.4 point release) - no new features from the 1st release of 2018 onwards - only bug fixes, everything should be better tested
Feature Release: 2019.1 (currently at 2019.1.2 point release (although there have been issues with updating the web page & downloads on sourceforge for various reasons) - has newer features that haven't been tested as widely
Next: currently sitting at 2019.2, contains untested new features, possibly not stable, definitely a moving target
2018.3 releases can be found here:
https://sourceforge.net/projects/flight ... se-2018.3/So FlightGear-2018.3.4.exe should be your most stable target on Windows, but if you're having issues...
2019.1 releases can be found here:
https://sourceforge.net/projects/flight ... se-2019.1/And here we have FlightGear-2019.1.2.exe
If you let us know your system specs (hardware, OS) & the kind of error you're seeing (flightgear spits out a crashdump the next time it starts usually), the people on here will usually help - the more info the better