Hello every one, here is some information I collected, which includes the model and firmware version that can support compatible with C4. If you have more information, please reply to complete the table. Thanks!
| Product | Model | Firmware Version |
Door Phone | E12 | E12 T30 12.61.1.101 |
| E16 | 116.31.2.1 | |
| R20 | R20 V3S 20.61.3.202 R20 T30 220.61.102.204 | |
| R26 | R26 V3S 26.61.5.101 R26 T30 226.61.1.101 | |
| R27 | ||
| R28 | 28.61.1.203 | |
| R29 | 29.61.2.401 | |
| X915 | 915.61.1.102 | |
Indoor Monitor | C313 V3S | 113.0.4.56 |
| C313 V2 | ||
| C315 | ||
| C317 | ||
| C319 | ||
| IT82 | ||
| IT83 | ||
| X933 |
