1.9 mods on 1.8?

[Motokid600]

Sorry if this is a dumb question, but to what extent can new mods be used on older versions? FAR for instance. Would I use the 1.9 version for a 1.8 game? I think its an obvious answer, but the reason I post is really about module manager. Seeing is how that hosts ALL mods should I be using the MM for 1.8? Or can I get away with 4.1.3? " For KSP 1.8.0 - 1.9.x "

[Gargamel]

Your best bet is to use the mod version for the version of KSP is was designed for:

 

But some of the latest mods only have a texture update or other new feature that might still be compatible with an older version of KSP.   But each mod will be unique in this, some new features might work, some won't.   The only real way to know is to install them one at a time to see if they work with your modset. 

[Nightside]

2 hours ago, Motokid600 said:

Sorry if this is a dumb question, but to what extent can new mods be used on older versions? FAR for instance. Would I use the 1.9 version for a 1.8 game? I think its an obvious answer, but the reason I post is really about module manager. Seeing is how that hosts ALL mods should I be using the MM for 1.8? Or can I get away with 4.1.3? " For KSP 1.8.0 - 1.9.x "

There are some many mods that do so many different things that it is impossible to have a blanket statement for your question.

It seems like many mods were not affected by the 1.8 to 1.9 change and so many modders never needed to update and mods that still work in 1.9. Conversely some mods updated to 1.9 will work in 1.8 but if the mod uses something new in the latest KSP it won't be backwards compatible.