Version changes - here 2.0.3 - must be written into the following files:

libmng.h : 
=======================
#define MNG_VERSION_TEXT    "2.0.3"

CMake/vers.cmake:
=======================
SET(MNG_VERSION_MAJOR 2)
SET(MNG_VERSION_MINOR 0)
SET(MNG_VERSION_PATCH 3)

makefiles/configure.ac :
=======================
define([MAJ_NR],[2])
define([MIN_NR],[0])
define([REL_NR],[3])

makefiles/version.mak :
=======================
MNGMAJ = 2
MNGMIN = 0
MNGREL = 3
MNGVER = 2.0.3