rebar/test/upgrade_project

Building version 0.1

rebar compile
cd rel
rebar generate
mv dummy dummy_0.1
cd ..
rebar clean
# start the release:
cd rel/dummy_0.1
bin/dummy console

erl> dummy_server:get_state().
erl> dummy_server:set_state(123).
erl> dummy_server:get_state().

Building version 0.2

# Now, in another terminal we prepare an upgrade..

# change release version numbers from 0.1 to 0.2 in
$EDITOR apps/dummy/src/dummy.app.src
$EDITOR rel/reltool.config

rebar compile
cd rel
rebar generate
# previous_release path is relative to your rel directory
rebar generate-appups previous_release=dummy_0.1
rebar generate-upgrade previous_release=dummy_0.1
tar -zvtf dummy_0.2.tar.gz
mv dummy dummy_0.2

Deploying with release_handler

mv dummy_0.2.tar.gz dummy_0.1/releases/

# Now use release_handler in the running erlang console for the deploy:

erl> release_handler:unpack_release("dummy_0.2").
erl> release_handler:install_release("0.2").
erl> release_handler:make_permanent("0.2").

erl> release_handler:which_releases().
erl> dummy_server:get_state().

Building version 0.3

rm -r rel/dummy

# Now repeat steps in 'Building version 0.2' and 'Deploying with release_handler'
# while replacing '0.2' by '0.3' and '0.1' by '0.2'.