I would say that that is at best 50-50.
However it is also possible that Telstra will delay again, given the political focus on this issue and the sheer number of affected devices and the customers who haven’t even stumbled upon the information yet that they are going to have a problem come 31 Aug.
If at all possible, you should not be using Telstra but that is generically good advice anyway 
. I’ve had VoLTE working on Voda since late last year.
I really don’t understand why a vendor (Broadmobi) wouldn’t make it a priority to get the necessary config for the largest mobile network operator but then maybe they are waiting for information from Telstra or are having difficulty getting cooperation from Telstra etc. You know the drill.
Just my opinion but this must be the least user-friendly firmware version numbering that I have ever seen!
FWIW, you can just do: mmcli -m any
since there is unlikely to be more than one modem.