Made the following changes as part of the migration to 1.4:

1. Renamed the IMT schema and odd files to imt_1_4_p5.
2. Changed the app variable imtSchemaFileName to reflect this.
3. Created XSLT files to convert 1.0 and 1.3 files to 1.4 (I've decided to cut of 0.9 files at this point; it was an early beta and anyone using the app seriously will have upgraded in the interim).
4. Tested the update system, and discovered a bug: when a temp file is created by the update XSLT, it's created in the temp folder, which means relative links to images are lost and the image can't be loaded. Changed the update function which calls the XSLT, so that it actually saves the temp file in the same folder as the original file. Tested this, and it works well.
5. Updated the docbook i/o files to 1.4. This revealed a couple of oddities in those conversions, introduced when I was using the app to create help documentation. Figured those out and fixed them. IMT 1.4 can now export to docbook, and import from docbook to IMT 1.4. Old docbook files are not imported; there's little evidence that anyone except for me is using this functionality, which is only just approaching maturity, so I think we're safe with this for the moment.
6. Tweaked and tested the Web View output. The changes are minor, but will affect the Mariage project code, so once IMT 1.4 is released I'll need to move it to the working machines for Mariage and make small changes to the XSLT on the Mariage site. Added a task for this at the end of January.
7. Began planning the zip functionality which will be the main new feature. I'll get into that in more detail tomorrow.