1.2. What does a LAMMPS version mean
The LAMMPS “version” is the date when it was released, such as 1 May 2014. LAMMPS is updated continuously. Whenever we fix a bug or add a feature, we release it in the next patch release, which are typically made every couple of weeks. Info on patch releases are on this website page. Every few months, the latest patch release is subjected to more thorough testing and labeled as a stable version.
Each version of LAMMPS contains all the features and bug-fixes up to and including its version date.
The version date is printed to the screen and logfile every time you run LAMMPS. It is also in the file src/version.h and in the LAMMPS directory name created when you unpack a tarball. And it is on the first page of the manual.
If you browse the HTML doc pages on the LAMMPS WWW site, they always describe the most current patch release of LAMMPS.
If you browse the HTML doc pages included in your tarball, they describe the version you have, which may be older.