DO NOT UPDATE OLD DOCUMENTS. OLD DOCUMENTS ARE MORE VALUABLE IN IMMIGRATION.
In Pakistan, new documents are often labelled as "LATE ENTRY", which causes significant issues in immigration..
An old, Urdu certificate is completely valid. I know a few relatives who translated theirs and had no issues.
They translated it privately, and the translator just added a statement saying that they are proficient in Urdu and English, and that they testify that the translation is accurate.