The vivo X23 is going to be announced soon, possibly even on August 20 - that date leaked through the Chinese company's virtual assistant, Jovi. Someone in China already seems to have his or her hands on a unit, however, as evidenced by the two spy shots you can see below.
They show a phone with a very small notch at the top of the display, akin to the one found in the Oppo F9 that recently became official. Oppo calls it a 'waterdrop' screen, and it's not surprising to see vivo using the same design as the two companies are both subsidiaries of BBK Electronics.
That said, we can't be 100% sure what's pictured here is actually the vivo X23 and not the Oppo R17, another device from vivo's sister brand which was announced a short while ago. Based on these angles it's tough to say with certainty that we're looking at a vivo and not an Oppo.
The vivo X23 should come packing the Snapdragon 670 chipset, an improved version of the under-display fingerprint reader, 3D face recognition, 8GB of RAM, and 6.4" size for that screen.