We have added a Knowledge Base article about creating index files for large validation files.  When we created index file support several years ago, storage space on devices was always at a premium.  In order to save some space, we used a 3-byte file pointer for the index entries.  This saved space, but limited the size of a validation file that could be indexed to 16MB.  At that time, no device had a 16MB storage area.

Now, however, many device have storage areas much larger than 16MB, so we are removing that restriction by moving to a 4-byte file pointer.  This allows a validation file size up to 4GB.  This update will be available with the release of ITScriptNet 2.4.