The "Byk Rak" racks with the red clips that bend and wear out are being replaced system-wide with Sportworks racks:
At this point I'd say they're at or beyond 50% new racks, based on my personal/limited experience.
There are a few older Sportworks racks in use-- the ones with the simple wheel hooks that look like umbrella handles-- mostly prototypes that were left in use after early trials, and some that came on used buses purchased from other cities.