Thanks for the link: this appears simply to be inaccurate:
B Version Displays as "6".
Which is incorrect for 719: which (I just checked a 719 system here) actually shows as '8':
2016-01-31 00:02:09,819 GMT*8*PEGA0055*13811[...]
I *believe* the number in position two of alerts is showing the version of the ALERT format : which *roughly* corresponds to the version of PRPC; but *probably* only gets incremented when a change is made to the actual ALERT format itself.
(Rather than say a new alert-type being added).
I'm pretty sure that the format of alerts has not changed between 718 and 719.