Upgrade from 0.91.4 to 0.93.2 failed

Today I attempted to upgrade but during the upgrade, the following is a portion of the upgrade progress where cryptography failed:

compilation terminated.
error: command ‘arm-linux-gnueabihf-gcc’ failed with exit status 1

ERROR: Failed building wheel for cryptography
Running setup.py clean for cryptography
Failed to build cryptography

Anyone know how to fix this problem?

https://community.home-assistant.io/search?q=cryptography

@VDRainer - that link was VERY helpful and resolved my upgrade problem. Thanks!