The characters \ / : ? * " < > | as well as leading and trailing spaces in file and directory names are generally problematic and cannot be used at all on some systems, e.g. the question mark on Windows.
Like last year we will be present at the (new) Icinga Summit in Berlin: On the second day we offer the workshop Write your own monitoring plugin in Python using the Linuxfabrik Libraries.
Let's Encrypt issues RSA certificates through two CA chains: the ISRG Root X1 chain and the ISRG Root X1 chain cross-signed by IdenTrust's vDST Root CA X3. The cross-signed chain ensures a high level of trust in Let's Encrypt certificates from the start.
