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 should be located in the OTP_ROOT/erts-EVsn/Vsn directory.

       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() is the current version of the release.

         * UpFromVsn = string() is an earlier version of the release to upgrade from.

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

         * Instructions is 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() is an earlier version of the release to downgrade to.

       When upgrading from UpFromVsn with release_handler:install_release/1,2, there does  not  have  to  be  an
       exact match of versions, but UpFromVsn can be a sub-string of the current release version.

SEE ALSO

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

Ericsson AB                                        sasl 2.3.4                                           relup(5)