upgrading from 5.x-1.5 to 5.x-1.8...

I need to upgrade a number of modules on a Drupal 5 site. The core is still 5.19, and many modules haven't been updated in almost 2 years.

I would greatly appreciate any suggestions/tips/warnings anyone can offer me related to upgrading the Image Assist module from 5.x-1.5 to 5.x-1.8 -- especially, for example, can I make this upgrade directly, or will that probably not work out so well?

Please let me know if I should provide any additional information about what's running on this site, etc.

Thank you very much in advance!