NAME

       relup - Release upgrade file

DESCRIPTION

       The release upgrade file describes how a release is upgraded in a running system.

       This  file is automatically generated by systools:make_relup/3,4, using a release resource
       file (.rel), application resource files (.app), and application upgrade files (.appup)  as
       input.

FILE SYNTAX

       In   a   target   system,  the  release  upgrade  file  is  to  be  located  in  directory
       $ROOT/releases/Vsn.

       The relup file contains one single Erlang term, which defines  the  instructions  used  to
       upgrade the release. The file has the following syntax:

       {Vsn,
         [{UpFromVsn, Descr, Instructions}, ...],
         [{DownToVsn, Descr, Instructions}, ...]}.

         Vsn = string():
           Current release version.

         UpFromVsn = string():
           Earlier version of the release to upgrade from.

         Descr = term():
           A  user-defined parameter passed from the function systools:make_relup/3,4. It is used
           in the return value of release_handler:install_release/1,2.

         Instructions:
           A list of low-level release upgrade instructions, see appup(5).  It  consists  of  the
           release upgrade instructions from the respective application upgrade files (high-level
           instructions are translated to low-level instructions), in the same order  as  in  the
           start script.

         DownToVsn = string():
           Earlier version of the release to downgrade to.

SEE ALSO

       app(5), appup(5), rel(5), release_handler(3erl), systools(3erl)