Google has announced that starting February 8, 2017, Chrome 53 and earlier will not be supported for Gmail. Starting then, a banner will be displayed indicating that an update is recommended for a safer experience. The current version of Chrome is build 56 for desktops.
The impact is most likely going to be felt by those who are still on Windows XP or Windows Vista. Chrome 49 was the last supported version for these Operating Systems and Google, as Microsoft themselves have done, are no longer supporting them. In Google’s announcement, users on XP and Vista are strongly encouraged to update to a new version of Windows.