Validity of document signed with expired digital signature

Yes. Digital signature may be applied to a document even if it is expired. 

I have got  assessment orders and notices which were signed by assessing officer with expired Digital Signature.

I just wanted to know if such order / notice signed using expired digital signature is a valid document or there is any provision under any law including Information Technology Act, 2000 which makes it compulsory to sign document with a valid Digital Signature only ?

I am attaching a screenshot of the DSC which has been expired for ready reference.

Please advise.

Your kind attention is drawn to the judgment of the Honourable Allahabad High Court delivered by the Honourable Justice J. J Munir in Transfer Application (CIVIL) No.  701 of 2021 dated 05.01.2022, having Neutral Citation No. - 2022: AHC: 1670 wherein at the end of the judgement, the Honourable Judge has mentioned by way of a note as under:

Note: Since my digital signature has expired and its renewal will take some time, the print out of the order has been taken and has been manually signed by us. This copy be uploaded with the stipulation as and when the digital signature is renewed or a fresh digital signature is obtained, the digital signature copy be uploaded after deleting the scanned copy.

The importance of a valid digital signature may be understood from the above very well, that if any document is to be signed, it has to be signed with a valid digital signature only.