The Gmail for Android app has been updated to version 6.11.27.141872707, and the new version brings support for some minor yet very welcome features.
You can now preview documents, spreadsheets and presentations, which you have in your inbox (or sent folder), even if you don't have a 3rd party app installed to open the specific format.
So you can see a preview of the document by scrolling down to the attachments. This does not work with password protected files, as you cannot even open them without the password (see the 2nd screenshot with the PDF, which is a protected one). If you tap on the file, and you don’t have an app to open it, you will be prompted to install one, from the Play Store.
Another new feature in the latest version of the Gmail app, is that it now lets you edit text in-line in mails. You can also copy and paste formatted content from the internet, to the Gmail app, and it will retain the formatted text style in the compose window.
The new version is available directly on the Google Play Store. So fire up the Play Store app on your phone, and download Gmail 6.11.27.141872707.