Here is a little more detail on that and note the string numbers for the different GPS fixes like GPS,DGPS, HP, RTK etc.  It is good to hear that they are finally addressing these differences.

 Field Description
1 UTC of position fix in HHMMSS.SS format
2 Latitude in DD MM,MMMM format (0–7 decimal places)
3 Direction of latitude (N=North, S=South)
4 Longitude on DDD MM,MMMM format (0–7 decimal places)
5 Direction of longitude (E=East, W=West)
6 GPS Quality indicator
0: fix not valid
1: GPS fix
2: DGPS fix
4: HP/XP converged and RTK fix
5: HP/XP unconverged and RTK float
7 Number of SVs in use, 00–12
8 HDOP
9 Antenna height, MSL reference
10 “M” indicates that the altitude is in meters
11 Geoidal separation
12 “M” indicates that the geoidal separation is in meters
13 Age of differential GPS data record, Type 1; Null when DGPS not used
14 Base station ID, 0000–1023