The nRF54L series is a new device to the nRF family, and during the bring-up of the chip from early engineering samples to mass production devices there have been quite a few releases of the nRF54L15 DK's. Some kits have early engineering samples that are no longer recommended for development, others may have errata issues that are only handled in specific nRF Connect SDK releases. This page will try to give some pointers to what you should look for, and whether you want to order yourself a new DK or apply specific workarounds.
First, to find which revision you have of the nRF54L15 on your specific DK you need to look at the small device markings on top of the nRF54L15 IC you have on the DK. Usually there are 3 lines on top of the IC like this:
N54L15
QFAAB0
2433AA
From the second line QFAAB0 I can find it's an revision 1 in this case:
https://docs.nordicsemi.com/bundle/comp_matrix_nrf54l15/page/COMP/nrf54l15/nrf54l15_ic_revision_overview.html
Based on the revision information I can find which nRF Connect SDK that is supported:
https://docs.nordicsemi.com/bundle/comp_matrix_nrf54l15/page/COMP/nrf54l15/nrf54l15_nrf_connect_sdk.html
I can also find the errata document I should check in specific for this variant:
https://docs.nordicsemi.com/bundle/comp_matrix_nrf54l15/page/COMP/nrf54l15/nrf54l15_doc_ref_design_files_overview.html
It's important to check the errata document for new and inherited anomalies, it may for instance be that new found anomalies do not have workaround in existing or older nRF Connect SDK releases.
https://docs.nordicsemi.com/bundle/errata_nRF54L15_Rev1/page/ERR/nRF54L15/Rev1/latest/err_L15.html
If you choose to work on an nRF54L15 that is not listed as supported in the nRF Connect SDK, this means that workarounds are likely no longer implemented in nRF Connect SDK, and you can experience issues listed for the specific variant you have.
Also be aware that implemented workarounds in many cases affect power consumption, moving to a newer revision without the workaround can in many case lower the power consumption.
Other links of interest:
https://docs.nordicsemi.com/category/nRF54L15-category
https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/app_dev/device_guides/nrf54l/index.html