A single Judge of Bombay High Court at Nagpur bench held that serving of summons through WhatsApp is valid.

From Para 2,

2. From the order it reflects that the case was posted for recording evidence of prosecution as the case being part heard. It is mentioned in the order
that the summons report was filed before the Court which discloses that summons is served through mobile phone to the witnesses. Witnesses namely Gunjal Prabhakar Kharabe and Dnyeshwar Sitaram Munde are absent. Service of summons through mobile phone to the witnesses is not allowed. Therefore, due to non-service of the summons by legal mode case is delayed and in that circumstances, the Special Judge has imposed the cost on the concerned Constable.

From Para 6,

6. From the impugned order, it reveals that as the summons was served through the mobile phone and therefore, the cost is imposed by the Special Court. Admittedly, there is amended provision in view of Section 70 of BNSS which deals with proof of service in such cases when serving officer not present. The sub-Section (3) specifically states that all summons served through electronic communication under sections 64 to 71 shall be considered as duly served and a copy of such electronic summons shall be attested and kept as a proof of service of summons as well as Section 530 of the BNSS also deals with the aspect of trial and proceedings to be held in electronic mode

Citations: [2026:BHC-NAG:2733]

Other Sources:

Index of such remedies from Judiciary are here.