Instructions to download sources from GIT repository, specific for stable branch 5.1 (release series v5.1.x).

Direct download of sources from GIT for latest Kamailio v5.1.x.

  git clone --depth --no-single-branch 1 https://github.com/kamailio/kamailio kamailio
  cd kamailio
  git checkout -b 5.1 origin/5.1

Note: if your git client version does not support –no-single-branch command line parameter, then just remove it.