On booting EspoCRM, the following warning is displayed in the system logs:
[444092.044400] inithooks[2568]: /usr/lib/inithooks/bin/espocrm.py:13: DeprecationWarning: 'crypt' is deprecated and slated for removal in Python 3.13
The current version of Python installed in the appliance as of TKL v18.0 is 3.11.2.
Apparently new minor versions of Python are released annually. Python 3.11 was released on 24.10.2022 and 3.12 was released on 02.10.2023. So, we have time until Oct 2024 (+ the time it takes for the new Python version to get to Debian repos, but I would not rely on that) to fix this.
The simplest fix is replacing this use of crypt with a more modern alternative like bcrypt or calling the provided library function to hash the password and set it via PHP instead.
More detail about the crypt deprecation here.