Changes in 1.5.6 are in bold
* Make sure everything is committed that should be in the release
* Update the language files, call linguist update and release
* Remove all incomplete languages from the chessx.pro file and the chess.qrc file
* Update ChangeLog, ChangeLog.txt file
* If year was changed, update year in Copyright header line of source files
* Change the version number in src/database/version.h
* Change the version number in mac_osx/Info.plist
* Change the version number in the pkg template (macOS)
* Change the version number in the setup.iss file (windows installer)
* Change the version number in the mac_deploy_dyn file (mac os installer)
* Change the version number in the make_tarball file (linux installer)
* Compile and verify that it works correctly.
* Commit changes
* Set the current release into chessx.sourceforge.net/versions/current.txt
* Update translations in chessx.sourceforge.net/translations/dict.txt and .qm
* Tag release in github:
git tag vM.m.r-lw
git push origin vM.m.r-lw
M = Major version
m = minor version
r = release