Google is retiring its iconic Catull font logo in favor of a new sans-serif logo, unveiled in the above video. Here's a before-and-after slider:
Alternatively, Google has provided a handy GIF, which also highlights the new multicolored "G" logo the company will be using going forward:
Google VP of product management Tamar Yehoshua and director of user experience Bobby Nath explained the move as intended to improve experience on mobile devices: "We’ve taken the Google logo and branding, which were originally built for a single desktop browser page, and updated them for a world of seamless computing across an endless number of devices and different kinds of inputs (such as tap, type and talk)."
The basic color scheme — blue "g"s; red "o" then yellow "o"; green "l"; red "e" — is unchanged, but the new design is still the biggest update since 1999, when Google abandoned this logo:
For this one:
The latter went through some modifications over the years, most notably getting flattened down in 2013; Ashley Feinberg at Gizmodo has a nice history of the logo's subtle changes. But its overall structure and font persisted.
Google designers Alex Cook, Jonathan Jarvis, and Jonathan Lee explain in a post on the logo change that they developed a wholly new typeface, called Product Sans, to use for the logo. Product Sans was previously featured in the logo for Alphabet, Google's new parent company due to a corporate reorganization in August.