A post on the Battle.net Forums offers a status report on the planned version 1.13 patch for Diablo II first mentioned in April, adding some detail to their terse statement on the topic a couple of weeks ago that said "higher priority issues" were causing a delay. This turns out to have been a Warcraft III custom map exploit that's described in this forum post, and once their fix for that is released, they can return their attention to the Diablo II patch (thanks Rhialto). Here's a bit:

The Warcraft III patch is now on the Public Test Realm (PTR) and testing is progressing. Once that patch is released work can shift back to Diablo II and the 1.13 patch, and we'll be working to getting that patch up on its own PTR as soon as possible. This could be a matter of weeks. Once it's up and in a testing state for all of you, it's then going to be a matter of ensuring the features are good and it's a solid patch. The more people we have testing the patch and providing valid feedback, the better the patch will be, and hopefully the quicker it will be released. So that's my challenge to you. You've been waiting a long time, you want an awesome patch, you want a reset. To get all that, we need good solid testing and feedback, reproduction steps for bugs, detailed descriptions of issues or errors, etc. So once this goes live on the PTR, I expect some crazed-youruinedtheeconomy-testing.