Continuous serial bill nos

Yes, he can continue

Rule 46 (b) of the CGST Rules 2017, which specifies that the tax invoice issued by a registered person should have a consecutive serial number, not exceeding sixteen characters, in one or multiple series, containing alphabets or numerals or special characters – hyphen or dash and slash symbolized as “-” and “/” respectively, and any combination thereof, unique for a financial year.
So, You can continue the serial number or can change the serial number series from new F.Y as per your choice

Note : Your bill number should not be same as old isssed bill no, otherwise taxpayers may face problem while generating E-Way Bill on E-way bill system or furnishing their Form GSTR 1 or for applying for refund on GST Portal.

Ok
thanks sir

Your most welcome, sir