Similar to the smart reply feature seen in Google's Inbox app, it learnt from the user's behavior to adapt its suggestions over time.

[6] Additional features include "Whisper Shout", which allows the user to increase or decrease the size of a message to represent volume,[23] and the ability to draw on photos before sending them.

[24] In March 2017, a GIF library was added in the compose bar, as well as easier one-tap access to the Google Assistant, and animated emoji.

[25] Also in March was an update that let Android users send various types of files, including PDFs, documents, APKs, ZIP archives, and MP3 tracks through Allo.

[29][30] Later the same month, Fast Company reported that Google updated Allo to add cartoon stickers on selfie photos, powered by artificial intelligence technology capable of producing "563 quadrillion face" animations.

[34][35] In June, the ability to make Google Duo video or audio calls directly from Allo chats was included.

[42] PC World's Mark Hachman gave a favorable review of Allo's virtual assistant, saying that it was a "step up on Cortana and Siri".

"[44][45] Thai Duong, a co-lead of Google's product security team, wrote in a personal blog post that he would push for the addition of a setting that would let users have the encryption on all the time.

[48][5] At launch, Google revealed that they would instead store all non-incognito messages indefinitely (or until the user deleted them) in order to improve the built-in "smart reply" feature.

[48] Russell Brandom of The Verge commented that "the decision will have significant consequences for law enforcement access to Allo messages.