Looking to come back

Hey everyone. I am looking to come back to the silent hunter game series or sub simulation in anyway. about 5-7 years ago I met some guys playing fsx back then and they introduced me to SH4. I didn't think much of it at the time, sense I was only about 18 and wasn't really interested in sub sims. But then recently I was watching Hoosiers, being from Indiana, I decided what other movies Gene Hackman play in. I saw Crimson Tide and read it's description and thought oh what the hell, sure lets watch it. WOW! I was amazed. Then I watched other submarine movies and documentaries and thought this is what I was missing?! So here I am again. Now down to business. I am thinking of buying either SH4 (the one I played) which from what I have seen and heard is the most popular of the series OR SH5 which is the most recent one. I know you can use mods on SH4. BUT, is there still multiplayer available, or no? Are there alternatives? Now SH5 being the most recent, I saw that there multiplayer went down on November 1st 2016. Is there still and alternative or no? Do mods work with SH5? I am thinking of buying it being the most recent Silent Hunter game, and kinda only being 7 years old.

Well there all that is. Thanks guys.