How to know the version of your current OSM installation
From OSM Public Wiki
From Release FOUR, in order to know the version that you have installed you only need to search the osm-devops package installed in your system:
dpkg -l osm-devops ||/ Name Version Architecture Description +++-================================-=====================-=====================-====================================================================== ii osm-devops 4.0.1-1 all <insert up to 60 chars description>