MIUI 9.5 is currently rolling out to xiaomi Redmi Note 4. The roll-out is said to be selective according to Mi community post so not everyone will receive it at this moment .
The selective MIUI 9.5 ROM is the Company stable ROM and not a beta version at all. The Xiaomi MIUI 9.5 Stable ROM includes the much awaited Notification Shade feature. It is essentially a quick reply feature with which you can reply to a message directly from the notification pane. Additionally, the new MIUI 9.5 update is said to bring the February security patch.
Mi Community post said, Xiaomi is rolling out the MIUI 188.8.131.52 NCFMIFA for some Redmi Note 4 smartphones. Apart from the February security patch, the update is said to bring new ringtones, lock and unlock sound, and charging sounds Global Stable ROM.
The posts suggest that it is a Nightly Build (selective). The company is known to roll out stable nightly builds of its MIUI updates to get user feedback before considering to push it out to global rollout.