Find out Requires WP tag for a plugin when submitting it

Yepp, if you really only use that hook, that would be the way to go. But it’s pretty likely you also use a couple of WP functions…if so, you should check these functions, too, before going too low with your required version.

Generally, i wouldn’t go below 2.0 (which i smore than 5 years old) for any new plugin. I think even going lower than 2.5, which is about 3 years old, is unnecessary.