In order to use some newer functions like ST_RemoveRepeatedPoints() (for geoshape optimizations`, we need version 2.2.0+. Our current version -- SELECT PostGIS_full_version();
POSTGIS="2.1.4 r12966" GEOS="3.4.2-CAPI-1.8.2 r3921" PROJ="Rel. 4.8.0, 6 March 2012" GDAL="GDAL 1.10.1, released 2013/08/26" LIBXML="2.9.1" LIBJSON="UNKNOWN" RASTER
2.1.4 is over 2 years old - http://postgis.net/docs/release_notes.html#idm38514