# Creating UDTs with MQTT Devices

**URL:** <https://forum.inductiveautomation.com/t/creating-udts-with-mqtt-devices/51048>\
**Category:** Ignition\
**Created:** [September 16, 2021, 8:37pm UTC](https://forum.inductiveautomation.com/t/creating-udts-with-mqtt-devices/51048 "2021-09-16T20:37:02Z")\
**Posts on this page:** 1\
**Showing post:** 16

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**Author:** ![Theodorska](https://avatars.discourse-cdn.com/v4/letter/t/34f0e0/32.png) [@Theodorska](https://forum.inductiveautomation.com/u/Theodorska)\
**Post date:** [January 17, 2025, 9:03am UTC](https://forum.inductiveautomation.com/t/creating-udts-with-mqtt-devices/51048/16 "2025-01-17T09:03:29Z")

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Update: nevermind, backfill is possible with referencetags [[FEATURE] Allow reference tags to receive backfill data from sources like MQTT tags - #16 by jhottell](https://forum.inductiveautomation.com/t/feature-allow-reference-tags-to-receive-backfill-data-from-sources-like-mqtt-tags/48261/16) had my answer

If I have understood this response and thread correctly, you use reference tags for interacting with the MQTT data, but you set up history directly on the incoming MQTT tags to allow backfill? Isn't it now possible to allow back fill in the reference tags tag group if we choose to set up history with them? Or should we continue to keep history enabled directly on the incoming mqtt tags?

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