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Home > Zooz Light Switches > ZEN21 On/Off Light Switch > ZEN21 On Off Switch Change Log
ZEN21 On Off Switch Change Log
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Here are the updates and improvements we made to the ZEN21 switch model so far.

VER. 1.0 (released 6/2016)

Original release.

  • Included screwless wall plate
  • Did NOT include neutral jumper
  • Did NOT include 3-way functionality (single pole only)

Firmware: 20.16

  • No advanced settings available

VER. 2.0 (released 6/2017)


  • Removed wall plate
  • Added neutral jumper
  • Added Direct 3-way solution
  • Added logo on paddle

Firmware: 20.15

  • Added advanced settings for paddle control and LED indicator mode

VER. 2.01 (released 12/2017)


  • Removed logo from paddle

Firmware: 20.15

  • Added a setting to enable/disable LED indicator
  • Added communication signaling from LED indicator (blinks when in inclusion/exclusion mode)

VER. 2.02 (released 10/2018)

Firmware: 20.15

  • Added a setting to control status after power failure

VER. 3.0 (released 3/2019)


  • Updated back cover for easier installation (larger terminal holes)
  • Added foam to packaging

Firmware: 3.0

  • Changed association settings to send separate reports for manual and Z-Wave control
  • Added S2 security
  • Added the ability to switch between LED modes with 6 quick clicks
  • Added Built-in Timer
  • Added the ability to reset the switch to factory settings from the device directly
  • Added the ability to control load by pressing any of the paddles
  • Added OTA firmware updates

VER. 3.01


  • Made the LED indicator smaller
  • Terminal screws arrive loose (unscrewed) for easier installation

Firmware: 3.01

  • Added scene control
  • Added the ability to disable physical control

VER. 3.02

Firmware: 3.02

  • Reduced manual control delay related to scene control functionality

VER. 3.03

Firmware: 3.03

  • Added the ability to disable Z-Wave control together with physical control
  • Added on/off reports to the hub and LED indicator status changes with disabled physical / Z-Wave control

VER. 3.04

Firmware: 3.04

  • Added the ability to adjust reporting behavior for disabled physical control
  • Added 3-way switch type setting to use momentary switches (like the ZAC99) in 3-way, 4-way, or 5-way set-ups without configuration limitations

VER. 4.0 (released 9/2020)


  • Removed side heat sink tabs

Firmware: 4.0

  • Changed the paddle sequence for enabling smart bulb mode (aka disabling the relay / physical control) to 4-down-and-hold for 10 seconds (tap the lower paddle down-down-down-down'n'hold)

VER. 4.01 (released 10/2020 as OTA)

Firmware: 4.01

  • Corrected the reporting behavior for smart bulb mode with physical and Z-Wave control disabled
  • Changed power outage behavior in smart bulb mode
  • Applied timers to status reports in smart bulb mode
  • Improved single-tap and long-tap timing for scene control triggers

VER. 4.03 (released 11/2020 as OTA)

Firmware: 4.03

  • Adjusted behavior for direct association (report sent anytime the paddle is pressed, regardless of the status of the switch)

VER. 4.05 (released 9/2021 as OTA)

Firmware: 4.05

  • Corrected the supervision command class for S2 implementation
  • Improved the reporting behavior for smart bulb mode with physical and Z-Wave control disabled
  • Added a setting to change scene control paddle mapping (parameter 16)
  • Added a setting to disable programming from paddles (parameter 17)


This model has been discontinued and replaced with the ZEN71 switch. No further updates are planned for the ZEN21 device.

If you have version 3.0 or higher, you can update the switch via OTA firmware updates, you can access all firmware files here after you register your product and create an account here. Questions? Just reach out to our tech support team, we're here 7 days a week!

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