Can you play newer updates of minecraft on an older server?

Please help! Minecraft recently updated to 1.7.5. I have a bukkit server with a ton of mods and a really cool world that i've been using for years. I'm port forwarded correctly, and my server runs without errors. But its a 1.6.4 Server and all of my friends who have updated to 1.7 can't connect. Do I need a 1.7 server? Because bukkit doesn't have any stable releases of one to my knowledge. Can we all just download 1.6.4 and not update and play on my server until bukkit releases a stable 1.7? Sorry if this is nooby i'm not that network savvy.

Sorry but you can't update your server to 1.7 if you were were you would need to start over from scratch and it doesn't seem like you want to do that. But what you can do is in the minecraft launcher and to the left of the big play button it should say Profile and below that new profile and edit profile.
1. Click "new profile"
2. Where it says profile name, name it whatever
3. Where it says "use version" put in 1.6.4 then press save profile
Now you can play minecraft on the old profile (1.7.4) and now on 1.6.4. This will connect to your server and yo can play. Just tell other people who play on you server to go back to 1.6.4 by doing the steps above.
Please check out my Youtube Channel MK BreakAway, It would really help.