Series 40 is a software platform and application user interface (UI) software on Nokia's broad range of mid-tier feature phones, as well as on some of the Vertu line of luxury phones. It is one of the world's most widely used mobile phone platforms and found in hundreds of millions of devices. Nokia announced on 25 January 2012 that the company has sold over 1.5 billion Series 40 devices. S40 has more features than the Series 30, which is a very basic OS. They are not used for smartphones, in which Nokia primarily uses Windows Phone, and up until 2012 Symbian. However, in 2012 and 2013, several Series 40 phones from the Asha line, such as the 308, 309 and 311, have been classified as "smartphones".
The platform is to be replaced with the Nokia Asha platform.
Series 40 was officially introduced in 1999 with the release of the Nokia 7110. It had a 96 × 65 pixel monochrome display and was the first phone to come with a WAP browser. Over the years, the S40 UI has evolved from a low resolution UI to a high resolution color UI with an enhanced graphical look. The third generation of Series 40 that became available in 2005 introduced support for devices with resolutions as high as QVGA (240×320). It is possible to customize the look-and-feel of the UI via comprehensive themes. A list of all Series 40 devices can be found on the Nokia web site.
It provides communication applications such as telephone, internet telephony (VoIP), messaging, email client with POP3 and IMAP4 capabilities and Web browser; media applications such as camera, video recorder, music/video player and FM radio; and phonebook and other personal information management (PIM) applications such as calendar and tasks. Basic file management, like in Series 60, is provided in the Applications and Gallery folders and subfolders. Gallery is also the default location for files transferred over Bluetooth to be placed. User-installed applications on Series 40 are generally mobile Java applications. Flash Lite applications are also supported, but mostly used for screensavers.
Web browser 
Support for SyncML synchronization with external services of the address book, calendar and notes is present. However with many S40 phones, these synchronization settings must be sent via an OTA text message.
Software platform 
Series 40 is an embedded software platform that is open for software development via standard or de facto content and application development technologies. It supports Java MIDlets, i.e. Java MIDP and CLDC technology, which provide location, communication, messaging, media, and graphics capabilities. S40 also supports Flash Lite applications.
See also 
- "Forum Nokia - Nokia Series 40 Platform". Nokia. Retrieved 2010-10-27.
- "Nokia has sold over 1.5 billion Series 40 phones". Retrieved 2012-01-25.
- "Series 40 UI Style Guide – Forum Nokia". Nokia. Retrieved 2008-09-26.
- "Carbide.ui Theme Edition (can be used to create S40 themes) – Forum Nokia". Nokia. Retrieved 2011-05-16.
- "Device specifications, filtered for Series 40". Nokia. Retrieved 2012-06-01.
- "Working with Nokia Series 40 Flash Lite content – Adobe Developer Center". Adobe Systems. Archived from the original on 2008-05-18. Retrieved 2008-09-26.
- "Developing Scalable Series 40 Applications, A Guide for Java Developers". Addison-Wesley. Retrieved 2008-09-26.