Upgrading the calendar system is usually very straightforward.  Since all of
the data is stored in the database, changing out the files on the site shouldn't
threaten the data at all.

Except as noted below, the procedure for upgrading versions is as follows:
  1) Unzip the new version into a temporary location.

  2) Copy the "calendar.properties" file from the "WEB-INF" folder of the
     current installation (old version) to the "WEB-INF" folder of the new
     version.

     a) If you have changed any of files beyond "calendar.properties" (e.g.
        updated the template files to change the design), those changes will
        need to be manually moved into the new version's files.  This could
        be more complicated than simply copying the changed files over the
        upgraded versions, since the upgraded versions may include changes
        that weren't in the original files you modified.
        That procedure is left as an exercise for the reader.

  3) Delete all of the files in the current installation (old version).

  4) Copy the new version into place where the old version was.
  
  5) Use Tomcat's Manager application to reload the site (if it is setup) or
     just restart Tomcat.
     
VERSION-SPECIFIC INSTRUCTIONS:

Upgrading 3.5.1 to 3.6.0:
  The initialization parameters have moved from the "web.xml" file (in the
    "WEB-INF" folder) to a new file named "calendar.properties" (in the same
    folder).  The files are in different formats (the new format is much
    friendlier), so the values must be manually copied from one to the other. 
    Once that is done, the old "web.xml" can safely be overwritten with the new
    version.

Upgrading 3.6.0 to 3.7.0:
  Run the calendar_3_6_0_to_3_7_0.sql file against the MySQL database to update
    its structure.
  Do not follow Step 2 above -- the calendar.properties file now contains two
    new values.  The changed values from the old calendar.properties file
    should be copied into the new file.