GSAK can generate one or more databases from your GPX files.
Please note that the offline cache view is only as good as the data provided in the GPX file. If you are getting your GPX files from a source other than the pocket queries from www.geocaching.com (for example, RobLisa) then not all the information displays in the offline view.
When you convert a GPX file you have two options:
Newer Only: The cache information is only updated if the GPX file you are converting is newer than the last updated date in the database. This is the default and recommended setting as it allows you to convert GPX files in any order you like, making sure that the offline database has the most recent history available. However, it is strongly recommended that you do convert your GPX files in date sequence.
Always: There may be times when you want to force a GPX file to update the offline database even though the information is older. (For example, you may want to see older logs from a previous version of the GPX file.) You can always go back later and convert a newer GPX file to get the most current data.