Do you need the anniversary upgrade to use normal mods?

[Red Sabre]

It's been ages since I played good'ol skyrim and I don't know if my old mods still work withouth the anniversary edition

[Rez Elwin]

If you're referring to the paid DLC, then No, it's not required.

[Greenegg]

that's going to depend on the mod.
Check their requirements. If a mod doesn't say anything about it, then no you don't need to buy it.

[Red Sabre]

Thanks

[Morgan Fun Gamer]

You can still use mods if you don't own Anniversary Edition but some mods might require Anniversary Edition to work.

[Skumboni]

AE is a Creation Club Crap Collection and you do not need it to use the good mods at Nexus.

[Ilja]

Many mods will make difference between AE and SE. This is not a reference to DLC, but to game version.

There are still some people lingering with game version that didn't get compiler update. This was understandable at first, because update required mods to update as well - and not every mod author was available to do so.

These days every relevant mod has been updated, of or replaced by another one. If some niche mod didn't get either updated or replacement, then no one has seen it important enough to get reworked. Skip and move on.

I have been strongly against the version naming scheme for SE. It is misleading to new players, who might expect that AE points toward Anniversary Edition requirement. This is not usually the case. As said above though, always check requirements. Some mods are especially made for Anniversary Edition content, though Nexus saw it fit to limit CC patches in their service.