Question about multimeter resolution
Basically yes with some restrictions.  The lowest range is 400 mv and the meter has a full scale of 3999 counts.  That means that on the 400 mv range, the least significant digit is indeed 0.1 mv.  However, internal noise or external pickup may limit being able to actually measure a voltage that low. Also,  there is a minimum accuracy of plus or minus 1 count which represents 0.1 mv on the 400 mv scale.  Thus the actual voltage could be 0.2 mv for a 100% error.