Hello,
after upgrading to oc 9.1.4 I got the warning about code signing:
https://doc.owncloud.org/server/9.1/admin_manual/issues/code_signing.html#fixing-invalid-code-integrity-messages
I found a problem about the documents app:
sudo -u www-data /usr/bin/php -f occ integrity:check-app documents
- EXCEPTION:
- class: OC\IntegrityCheck\Exceptions\InvalidSignatureException
- message: Signature data not found.
https://doc.owncloud.org/server/9.1/admin_manual/issues/code_signing.html#errors
It seems to be missing the signature.json file.