Let’s say you stopped playing RuneScape game in 2007 for some reason. And now you are starting up RuneScape again. You’ll discover that a lot of things have changed. First of all Old School RuneScape have appeared separately from RuneScape 3. You may be curious what precisely is the difference between the two. Is OSRS (or RS2007, both short for Old School RuneScape) is like a separate site from RuneScape 3 (aka RS3)? And is OSRS game like it was in 2007?
Well, there are actually lots of differences. Old School RuneScape (OSRS), also called RuneScape 2007 (RS2007, RS07), came out in 2017 as a request by players who wanted to play their favorite game in the form they knew well and to which they were already strongly attached. Therefore, Jagex decided to launch Old School RuneScape: a version of RuneScape from the year 2007. They formed a dedicated to it developers team and allowed the OSRS players to vote on updates if they like. Back then it was members-only and was supposed to have few updates, maintenance mostly, but seeing how huge of a hit OSRS was, Jagex soon made it a full game, available to free-to-play too, with constant updates, not only fixes, but new content as well, such as Chambers of Xeric or Theatre of Blood. So today Old School RuneScape is not the same as it was back in 2007.
As far as RuneScape 3 is concerned, the game has been even more modified and much new content has been added. So you stopped playing RuneScape game in several years ago, RS3 would now be even more alien to you than OSRS. Yet, it has the original combat system (which according to many is a disadvantage) and you could still play like you did in the past.
Oh, yeah, one more thing: If you start to play Oldschool Runescape again, you would begin at all first levels and would have no RS items. This is because, as already mentioned, players data was not included in the backup. But it would not affect your Rs3 account, as they are separately saved files.