Hey Martin,
Well, yes you can use your comments from 1.0.15 - you will need maybe to make some small db changes (but I think that if you follow the right update path explained in the documentation, you'll be fine).
Now the thing is - 1.5 is going to go out of life pretty soon... So you will need to one time migrate to 1.5 and then migrate again to 2.5...Or you can just go 1.0 to 2.5, but you will need some php + db knowledge... In any case 1.5 is not the right version number anymore
Kind regards,
Daniel