I was using the last M6 snapshot but just updated to today's build. Also I updated to 05/13 PA gapps. It's 4.3.25 Google Play Services and mirroring keeps working.
Just to let you know, my S4 is the M919 build which uses Snapdragon 600 SoC. Maybe i9500 won't work since it uses Exynos SoC.