One of the currently used certification chain looks as indicated below.
All certificates issued under Juur-SK chain expired on 26th of August 2016. New certificate chain can be found on this article.
This scheme indicates that several OCSP validity certification service certificates have been issued with each certificate of the certifier as the lifetime of the OCSP validity certification was shorter than the lifetime of the certificate of the respective certifier. Support for ALL these OCSP certificates must be configured in digital signing systems as checking the validity of the given digital signatures is otherwise impossible.
All the certificates described in the article can be downloaded at the address http://www.sk.ee/certs/.