Summarises the steps spelt out in full here

Get code

Pull down latest, create branch:

git checkout master
git pull --ff-only
git checkout -b prepare/isis-1.2.3-RC1

Sanity check:

rm -rf ~/.m2/repository/org/apache/isis
mvn clean install -o

Switch to correct directory

Switch to the directory containing the (parent of the) artifact(s) to be released, eg:

cd core

Check code

Update parent version to non-SNAPSHOT (including tck project, if any):

vi `find . -name pom.xml | grep -v target`

Newer dependencies:

mvn versions:display-dependency-updates > /tmp/foo
grep "\->" /tmp/foo | sort -u

Missing license headers in files:

mvn org.apache.rat:apache-rat-plugin:check -D rat.numUnapprovedLicenses=50 -o
for a in `find . -name rat.txt -print`; do grep '!???' $a; done

Missing/spurious supplemental-models.xml:

mvn license:download-licenses
groovy ../scripts/checkmissinglicenses.groovy

Release

Prepare then perform (switch to cmd.exe if on Windows):

mvn release:prepare -P apache-release -D dryRun=true
rm release.properties
mvn release:prepare -P apache-release -D skipTests=true
mvn release:perform -P apache-release