Had some trouble [again] making the morph injection created in Poser 11 to work in Poser 10. It appears that the major incompatibility is with the animatable origins required by the morph. Even Poser 11 option to export morph injections tends NOT to include the animatable origins. All of the scripts I have in Poser 10 do not include those. I first tried to hack the P11 files to include the animatable origins, but then they only work in P11, and not in P10. The issue was that the animatable origins created by P11 have no effect in P10 when it comes to morph injections.
The solution was to save the morph as a CR2 in P11, load it back in P10, save it back to the library in P10, and then manually convert it to a morph injection (P10 doesn't have this option), and then hack the file to manually include the animatable origins that were extracted from the P10 file. Only then the morph has worked in both P10 and P11.
It becomes evident that contents created in P11 are not compatible with P10. I can force the compatibility with the complex acrobatics described above, but I am not sure if that would work with other kinds of contents. This backwards incompatibility might be the result of SMS dismissing the original dev team and allowing newbies to mess with the code. That was precisely when this issue has started, so I am making an educated guess.
Unless Rendo fixes the issues, chances are that content creators might stop supporting P10, unless they create the contents using it. However, P10 has a number of serious bugs on the content creation tools that will never be fixed, so I don't even consider it viable. To mention a few, morph deletion in P10 can delete any number of random morphs in addition to those that are selected, so you don't know what you are actually deleting. Another serious one is that the Morphing Tool in P10 cannot be used to correct or create JCMs due to a bug that was only fixed in P11. There are many others, but these 2 are more than enough to dismiss it as a viable option. Chances are that Rendo will only maintain the current P11 version, so P10 might never be fixed.
I have managed to make this morph compatible with both P10 and P11, but this method only works with morph injections. I know the P11 files are also incompatible with P9 and P10 in other areas, like materials and skeletal joints. Having that said, I am not sure if HW still supports P10, but in light of these issues, it seems unrealistic to expect things to work there. It took me 2 days to get the P11 files to work in P10 using all sorts of hacks.