I received the following official response to an email I sent regarding the recognition of years accumulated on a beige residence certificate, prior to the issuance of a 5 year biometric permit. It basically confirms the information that Julia Cross provided:
In response to your question, we would like to inform you that according to Article 16 of the Withdrawal Agreement, periods of legal residence or work in accordance with Union law before and after the end of the transition period shall be included in the calculation of the qualifying period necessary for acquisition of the right of permanent residence. This means that your residence periods in Greece before the end of the transition period are included in the calculation of the qualifying period necessary for acquisition of the right of permanent residence. Thus, since you continue to reside in Greece fulfilling the requirements set out in the Withdrawal Agreement, in 2023 you may apply for the residence document valid for 10 years and be issued with it, irrespective of the fact that your residence document expires in 2026 (it is not compulsory to wait for your current document to expire in order to apply for the residence document issued to permanent residents). For more information on this issue, please visit our website in the link: http://www.astynomia.gr/index.php?optio ... 33&lang=EN
For any other information or clarifications, you may also contact our Division on the telephone below.
Ministry of Citizen Protection
Hellenic Police Headquarters
Aliens & Border Protection Branch
Department of Citizenship, Homogeneous and European Union Citizens
Adr. P. Kanellopoulou 4, 10177 Athens Greece