Merge branch 'release/1.6.8' into develop

* release/1.6.8:
  Increment version number to 1.6.8
Fix uuid4 generation to 32bits (not necessary but clearer)
Thread Safe version of UUID4
Update release number to 1.6.9
Merge branch 'release/1.6.9'

* release/1.6.9:
  Update release number to 1.6.9
  Thread Safe version of UUID4
  Fix uuid4 generation to 32bits (not necessary but clearer)