Can't use function return value in write context

Adjust isLocal() on encryption wrapper

[encryption] handle encrypted files correctly which where encrypted with a old version of ownCloud (<=oc6)

Fix type annotation

Improve error messge text for app upgrade try (#15375)

Obviously should be an int

OCC commands to manage encryption

fall back to the ownCloud default encryption module and aes128 if we read a encrypted file without a header

fix layout for multiline buttons which are <a class='button'>

Fix collision on temporary files + adjust permissions

Block old legacy clients

fix encryption header error

testRewind tests reading and writing after rewind on an encrypted stream; testWriteWriteRead tests r+ mode