I've been thinking of late. With how many games the Flames play in the retro jerseys (any Canadian team matchup or Saturday night game, and perhaps more), as well how much they showcase the jerseys on the Flames site (only jersey the players on the backgrounds are in), I would wager that Flames are actually going to introduce the retro away jersey and make that and the home the new primaries. No reason for the Flames to remove the retro, and use it so much, if you don't intend to keep it in the future for frequent use. And since rumours indicate it's just one jersey, it may be just to compliment the retro home to make the full switch.
If that is indeed the case, I hope they go full retro, and remove the black stripe outline from the Flames logo as well. It'll unnecessary since black wouldn't be a colour present on the primary jerseys anymore. All the other teams that don't have black as a team colour don't feature a black outline. If they remove it, I think it would make the logo look sharper strangely enough. Really completes going back to that 'classic' look.
Compared to with black outline.
Now even if it is the case that it's a brand new jersey, if it still follows the theme of only red, yellow, and white being the colours on the jersey, the Flames should make the switch to remove the black outline if it's the intention to transition the new jersey into becoming the primaries in the near future.