The Gmail email service has received a spam filter update, which Google calls “one of the biggest security updates in years”, writes Ars Technica.

It is a new text classification system called RETVec (Resilient & Efficient Text Vectorizer) that has been integrated into Gmail. According to Google, it is able to recognize “hostile text manipulation” – emails with special characters and other elements that filters had difficulty distinguishing.

Gmail

Such letters often contain so-called “homoglyphs”. This is the name given to graphically similar characters that actually have different meanings. Google assures that RETVec is trained to detect such messages.

The model was trained using a new encoder that can efficiently encode all characters and words in UTF-8 format. According to the company, RETVec works in more than 100 languages.

The algorithm is based on the TensorFlow AI framework. Google says it has been testing RETVec “for the past year” and has already deployed the system in Gmail accounts.