Had contact with someone from Meraki Support. The person claimed it was supported.
So also send the case to my Account manager because I don't think it's true. But on the other hand. Another switch shows this with the same firmware version and running in Hybrid mode already.
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Meraki Cloud Monitoring: Compatible
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Meraki Cloud Management:
Compatibility Check     Status
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Boot Mode               INSTALL  - Compatible
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Switch#  SKU                                Bootloader Version              Network Modules
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2        C9200-48P          - Compatible    17.15.1r        - Compatible    C9200-NM-4X    - Compatible 
 
Compatible SKUs: C9200-24P, C9200-24T, C9200-48P, C9200-48T, C9200-24PXG, C9200-48PXG, C9200-48PL
Compatible NMs : C9200-NM-4G, C9200-NM-4X, C9200-NM-2Y, C9200-NM-2Q