After failing to flush out a better offer from an unnamed suitor, and following a stalemate with rival bidder Pendula, communications software business Whispir (ASX: WSP) has announced it is throwing its support behind a $74.3 million unconditional takeover offer by Soprano Design Technology.

Backed by substantial investor Potentia Capital, Soprano looks set to acquire the Melbourne-based Whispir for 55c a share.

With the offer set to expire this Wednesday, 10 January, the Whispir board has unanimously urged shareholders ‘promptly’ accept the unconditional Soprano offer in the absence of a superior proposal.

The Whispir board last week announced that it had been in discussions with another party regarding a potential alternative proposal.

“However, as at the date of this announcement, no superior proposal has emerged, or is likely to emerge, from these discussions,” the company says today.

“Further, the Whispir board confirms that there are no ongoing substantive discussions with Zipline Cloud Pty Ltd (Pendula).

“Accordingly, having made significant efforts to explore and progress all potential alternative proposals for your Whispir shares, the Whispir board now considers it unlikely that a superior proposal will be made for your Whispir shares before the end of the offer period.”

This is despite Pendula proposing a non-binding offer of 57c per share for Whispir, a bid that was conditional on Whispir’s founder and outgoing CEO Jeromy Wells buying into Pendula as part of the transaction.

Soprano, a Sydney-based Communications Platform as a Service (CPaaS) provider founded in 1994 by Dr Richard Favero (currently the company’s chairman), was forced to lift its original offer of 48c per share last month.

The previous offer by Soprano, which is already a substantial shareholder in Whispir, was rejected by the Whispir board following an independent expert’s report that deemed it to be ‘not fair but reasonable’.

Whispir today issued a sixth supplementary target’s statement in which the company says it has made ‘significant efforts to explore and progress all potential alternative proposals’ for shareholders.

While it had previously recommended shareholders hold out until the last minute to accept the Soprano offer, it was now urging them to accept immediately as it is unlikely that a superior offer will be forthcoming.

“Whispir shareholders should not assume that Soprano will extend the closing date of the offer period and Whispir shareholders who wish to accept the Soprano offer should act without delay,” the company says.

Wells, as a substantial shareholder, confirms he intends to accept the offer.

Soprano, which has a customer base of about 4,500 clients globally, helps users strategically integrate conversational AI, SMS, email, voice, IP messaging and social channels such as RCS, WhatsApp and Google Business Messages into a seamless and secure omni-channel experience.

Whispir’s platform automates communications between organisations and people, from SMS messages to email, forms to landing pages and social media.

Shares in Whispir last traded at 54.5c at 12.49pm (AEDT).