The latest firmware version for the DS-K2604T is V5.3.3 (released on March 2022). You can download the firmware from the Hikvision website or through their dedicated support portal.
You're looking for help with the DS-K2604T firmware!
The DS-K2604T is a Hikvision access control panel, and firmware updates can sometimes be tricky to navigate. Here's a helpful piece of information: