Here's a good breakdown of the camera system improvements:
DPReview iPhone 14Pro coverage
It looks like they've upsized both the main camera sensor and the ultrawide sensor so the effective apertures in both are still larger than in the 13Pro, though the differences may not be that great.
iPhone 13Pro
main camera
(26mm equivalent) = f//1.5 x 4.6x =
f/6.9 (35mm equivalent)
ultrawide camera
(13mm equivalent) = f/1.8 x 8.7x =
f/15.66 (35mm equivalent)
iPhone 14Pro
main camera
(24mm equivalent) = f/1.78 x 3.5x =
f/6.3 (35mm equivalent)
ultrawide camera
(13mm equivalent) = f/2.2 x 6.2x =
f/13.64 (35mm equivalent)