# W1 Pro - Can I downgrade the firmware from 03.26.CK\_Dark to 03.26.33-ARF-EI?

**URL:** <https://community.anviz.com/t/w1-pro-can-i-downgrade-the-firmware-from-03-26-ck-dark-to-03-26-33-arf-ei/2321>\
**Category:** Development Tools\
**Tags:** time-attendance\
**Created:** [February 6, 2025, 9:27am UTC](https://community.anviz.com/t/w1-pro-can-i-downgrade-the-firmware-from-03-26-ck-dark-to-03-26-33-arf-ei/2321 "2025-02-06T09:27:53Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![user4](https://sea2.discourse-cdn.com/flex020/user_avatar/community.anviz.com/user4/32/1183_2.png) [@user4](https://community.anviz.com/u/user4)\
**Post date:** [February 6, 2025, 9:27am UTC](https://community.anviz.com/t/w1-pro-can-i-downgrade-the-firmware-from-03-26-ck-dark-to-03-26-33-arf-ei/2321/1 "2025-02-06T09:27:53Z")

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How can i downgrade the firmware ? please send me a copy of 03.26.33-ARF-EI firmware.

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**Author:** ![Technical\_Anviz](https://sea2.discourse-cdn.com/flex020/user_avatar/community.anviz.com/technical_anviz/32/1143_2.png) [@Technical\_Anviz](https://community.anviz.com/u/Technical_Anviz)\
**Post date:** [February 18, 2025, 8:51am UTC](https://community.anviz.com/t/w1-pro-can-i-downgrade-the-firmware-from-03-26-ck-dark-to-03-26-33-arf-ei/2321/2 "2025-02-18T08:51:20Z")

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Hi,

May I know the SN of this device? We don’t recommend you downgrade the devices, as this might break the device.

May I ask why do you want to change the firmware?

Zac