When writing a a plug-in it is important to consider that a plug-in should be both backwards and forwards data compatible with other versions of the plug-in.

Data backwards compatibility means that a later version of a plug-in is able to load data created from a previous version of the plug-in. Two techniques that are useful for maintaining backwards compatibility are reference remapping and parameter block versioning.

Data forwards compatibility is demonstrated by the scenario of a company which uses a new version of your plug-in when creating assets, and sends the created assets as a Max file to its client who only has the old version.

Data forwards compatibility is required of plug-ins as of 3ds Max 2011 because of the introduction of the new save to previous feature,