At 16th of April, 2017 the Resolution of the Cabinet of Ministers of Ukraine «On Approval of the Rules for issuing visas for entrance and transit through the territory of Ukraine» No. 118 dated on March 1st, 2017 came into force. With new procedure of issuing visas to entry into/exit from the territory of Ukraine as well as new validity terms and legal ground for issuing visas you can learn in section "Visa Requirments" from the link attached below:
http://pakistan.mfa.gov.ua/en/consular-affairs/services/visas