Very pleased to announce that the 3DR GPS+mag module, which ran out of stock way too soon after we announced more than a month ago, is back in stock. Any remaining backorders are now being filled, and any product waiting for this should also be going out now. Thanks everyone for your patience on this one -- a combination of overwhelming demand along with supplier problems from the resin provider (the GPS uses a special translucent gray plastic) to the pad printer contributed to the long backlog (we've taken steps to ensure that it doesn't happen again.)
If you've been waiting to convert your APM 2.5 to an external mag for superior copter performance (instructions for doing that are here), this is your chance. It's also the standard for APM 2.6, which is designed from the start for an external magnetometer. I've converted all my copters to this and loiters/navigation have never been better.