Old School RuneScape is back online. Please see the most recent update below.Old School RuneScape is offline whilst we investigate an issue affecting the game.We're very sorry for any inconvenience caused, and we will restore service as soon as possible. We will endeavour to restore the game to its state prior to the emergence of the affecting issue. We don't yet have an estimated time for resolution.Thank you for your patience, and we'll continue to keep you updated.Update: 14:20. There's still no estimated time for resolution, though we're preparing the essential work needed to restore the game as detailed above. Again, apologies for any inconvenience and thank you for your patience.Update: 15:10. The work required to bring about restoring the game (a rollback) is now commencing. There's no ETA as to its completion.Update: 18:11. Old School RuneScape is back online.We'd like to thank all of you for your patience and understanding during the time Old School RuneScape was offline. Shortly after the weekly game update went live, it quickly became apparent that a damaging bug existed. We were able to spot it so quickly thanks to the honesty of the community who helpfully alerted us to it, and we made the decision to turn off the game worlds to prevent further effects on the game's economy while the situation was investigated.There was a lot of speculation as to what the bug was, and what was causing it. So in the interest of transparency we'd like to take some time to explain the issue.One of the team was implementing the code for the pickpocketing update. This involved producing stackable pouches that are treated as being coins. On death, the aim was to convert them into real coins, partly so that a PKer could get the value if applicable.When converting a stack of items into a stack of coins, it's appropriate to check that the calculation doesn't overflow the max integer limit of the game's language (2.1 billion). Unfortunately, the logic used for this calculation was incorrect, and when executed on stacks of other items (not the pouch itself) the result was to convert the stack to 2.1b coins.Regrettably, although the pouches were found to be acting correctly during testing, the flaw affecting other items was not spotted as it was not expected to have changed.Old School RuneScape has never experienced a rollback of any sorts before, and to set about restoring the game to an earlier state (prior to the bug) was an immense undertaking. The damaging effects of this bug led to a consensus quickly being reached, with the team resolved to undertake a rollback, if such a thing were possible. Subsequent investigation found that it might be possible, though not easily done.The intention of the team was to attempt to roll back players' saved games to the approximate time of the game update (11.30am BST). Finally we'd like to reiterate that we've never done anything like this before. It's possible some issues may still persist, but we assure you that we'll continue monitoring the situation to ensure that normal service is resumed.We're very much aware that players' other items are affected by this kind of rollback; sadly we were not able to restrict the effects solely to players who'd generated money from the bug, as coins are tradeable and the effects were far more wide-reaching. This means that players would have lost around 20 minutes of their activity. We're very sorry if you were fortunate enough to have received a rare loot-drop or something similar during that time.The vast majority of normal players are now able to return to normal play, but a small minority of players may be affected by an issue attributed to their save files which will prevent them from logging in. Whilst this can be readily resolved, unfortunately it must be fixed manually. The positive news is that we are automatically made aware of who is affected with each unsuccessful log in attempt. If you find yourself unable to log in because of this issue, we ask that you remain patient, and we'll restore your access to game as soon as we're able.Whilst we do acknowledge that the bug is a fault of ours, it became apparent that a number of players were quick to exploit it for personal gain, in such cases as players using the exploit to generate wealth to buy Bonds to redeem for Old School RuneScape membership. With this in mind we will be removing the illegitimately-gained membership which was received via bond redemption during the time the bug was live. Players who abused the bug will also see action taken against their accounts and will temporarily be removed from the game.Thank you again for your patience.