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Action Required: Transition to DCR-based KQL transformations by 31 March 2026 

Published date: March 31, 2023

On 31 March 2026, we will retire custom fields, a feature of Azure Monitor log analytics that allows extraction of data from logs to new custom columns. Before that date, you’ll need to transition to DCR-based KQL transformations, which provides all the functionality of custom fields plus new ones, including: 

  • Ability to produce multiple columns from a single input with a single KQL statement; 

  • Additional string operators, including ability to convert data types, manipulate strings and execute regular expressions; 

  • Scalable deployment options, debugging and troubleshooting capabilities. 


Required Action  

To continue parsing your logs into custom columns, transition to DCR-based KQL transformations by 31 March 2026. Custom fields not transitioned to KQL transformations by that date will stop working and corresponding log columns will remain empty. This will not affect data already ingested. 


Help and support  

If you have questions, get answers from community experts in Microsoft Q&A.  If you have a support plan and you need technical help, create a support request.  

  • Azure Monitor
  • Retirements

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