Particle system not working in 4.25

I have download old versions of the engine to check what particle system I can use or modify for my game from the free content, but when I migrate them to 4.25 most of them are almost invisible compared to beauty and rich original in the old version and in the best way only part of them is visible. Why something that works in old version is broken in new? Is that mean that If I purchase today particles they wont work next year/months with the new engine version.