We just downloaded the new release of Acad MEP 2013 and seems to work fine. However, when we save the drawing down to a Acad 2012 version we lose all of the piping content in the new 2012 drawing. This is the message we are recieving.
Also, the Piping Tool palettes are no longer working in the new saved 2012 drawings.
I am just going to copy and paste an answer that has been given several times on the forums. AutoCAD MEP 2013 is a file format release. This means it is not compatible with older releases.
Quote from Joshua Benoist from Autodesk
This is out there though the information needs to be spread around more. Please do what you can to help spread the information. Every 4th release historically has been a file format release and 2013 is no different. We see questions and surprises when users save their files in 2013 and then save back to an earlier version. Then proceed to open in an older release. The older release can no longer edit the AEC objects as intelligent objects. Users not familiar with past file format releases may be surprised.
2010 was a file format release. So 2011 and 2012 were on the same 2010 file format. 2011 and 2012 are backwards compatible with 2010. You can save and open between any of those 3 releases because they are on the same format. 2010, 2011, 2012 However, save a 2010 file to the 2007 file format version, and we get the same backwards compatibility issue as between 2013 and 2010 formats.
2013 is the 4th and start of a new file format. Files saved in 2013, then saved back to an earlier format cannot be edited in the prior format. They become proxy objects, and for the most part the graphics display the same. To edit them, we can Export To AutoCAD and then edit them as Core AutoCAD objects in the earlier release.
My advice is always to finish older projects in older release on the older file format. Start new projects on the new release and format.
Thank You for the information.
We did not know this and we may continue to work on 2012 until we get new projects in and we can use 2013.