It certainly has been a fractious environment since the lifetime upgrade offer was announced. I've read through most of the related threads on these forums just now and can see both sides of the fence:
1 - the long standing Sonarians who have chosen to purchase Platinum life time upgrades are concerned that they might miss out on some additional content offered to upgraders/new customers who make their purchase after 31/8/16. Based on the responses we have had from CW to date, such fears appear to be groundless i.e. all Platinum users will get the same rolling updates as and when they become available. Yes, this means that annual/monthly Platinum members will be paying more than those on lifetime upgrades, but a sale offer is by definition time limited. My understanding of the pricing model is that those who upgrade to Platinum will receive the same additional content as those who purchase Platinum outright as a new customer i.e. Drum Replacer, Vocal Sync, Dimension Pro and Rapture (full versions), Analog Track Box, Breverb, PX64, TS64, VX64, Tone2 Bitfilter2, Lounge Lizard, Strum Session 2, True Pianos Amber and Ultra Analog Session2.
2 - CW cannot possibly confirm what additional content may be available for any tier of Sonar users in the future (as this content will only be in the development stage but it seems more than likely that additional instruments, FX, console strips etc will not automatically be included in the rolling updates i.e. they will be offered as separate purchases with a possible discount for existing customers) There is more than sufficient confirmed content info available in the store now with which to make a purchasing/upgrade decision.