We need 3 plugins:
1. Convert Folder of Scores to Current Sibelius Version 2. Batch transpose 3. Convert folder to Music XML (preinstalled on Sibelius 7.5)
Using the plugins:
If transposing instrument but written as piano (make sure by listening and using a chromatic tuner): Use plugin Convert Folder of Scores to Current Sibelius Version to batch convert everything to current version.
Use plugin Batch Transpose to transpose everything (maj. 2 down in case of Bb instruments, Alto sax is in Eb, e.g. maj. 6 lower). Choose ‘Transpose by Interval’, ‘Save and close’ continue with Batch Transpose and do an instrument change
Batch convert to xml with the Dolet plugin.