The cut-price Raspberry Pi Model B computer has been given it's first major upgrade since its launch two years ago.

The Raspberry, which is popular in schools and among developers and hobbyists alike, has now been renamed the Raspberry Pi Model B+.

Announcing its introduction, the Raspberry website says: "We've often talked about our intention to do one more hardware revision to incorporate the numerous small improvements people have been asking for.

"This isn't a 'Raspberry Pi 2', but rather the final evolution of the original Raspberry Pi. We're very pleased to be able to announce the immediate availability, at $35 (£20.60) - it's still the same price - of what we're calling the Raspberry Pi Model B+."

What's new in the Raspberry Pi Model B+?

The Model B+ uses the same BCM2835 application processor as the Model B, runs the same software and still has 512MB RAM. But key improvements include more GPIO (general purpose input/output). The GPIO header has grown to 40 pins, while retaining the same pinout for the first 26 pins as the Model B.

The number of USB ports has also been increased from two to four USB 2.0 ports, and there is said to be "better hotplug and overcurrent behaviour". Also, the old friction-fit SD card socket has been replaced with a "much nicer push-push micro SD version".

In addition, there is lower power consumption. By replacing linear regulators with switching ones "we've reduced power consumption by between 0.5W and 1W", says Raspberry.

Other improvements include better audio with an audio circuit that incorporates a dedicated low-noise power supply, and a "neater form factor" by aligning the USB connectors with the board edge, moving composite video onto the 3.5mm jack, and adding four squarely-placed mounting holes.

The old machine will still be available though. Raspberry said: "To ensure continuity of supply for our industrial customers we'll be keeping Model B in production for as long as there's demand for it."