EDIT: likely this answer was not correct. There is hope ... 😉
Sadly, the release notes are wrong. I upgraded my MX64W to 17.6 but there was no AnyConnect. Meraki Support told me that there is no AnyConnect on this devices:
"Thank you for contacting Cisco Meraki Support.
The MX64 does not support Cisco Anyconnect at the moment. For more information about AnyConnect on the MX Appliance please refer to the documentation article below;
https://documentation.meraki.com/MX/AnyConnect_on_the_MX_Appliance#Caveats
I will set this case to closed. However, if you require any further assistance, please feel free to reach out by calling support or responding to this email and we can reopen the case and continue on from there."
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