Originally Posted by Mikeypants
To upgrade to BIS 2.5 you need to resend your service books.
To fully take advantage of some of the new possibilities of BIS 2.5 such as HTML email, install OS 4.5 onto your device.
4.5 hasn't ben released by O2 and doesn't look like it will any time soon, see quote below from O2 Support Forum:
We've been testing various releases of handheld code 4.5 for the BlackBerry 8700, Blackberry Pearl 8120, BlackBerry Pearl 8110, BlackBerry Pearl 8100, BlackBerry 8800, BlackBerry 8820, BlackBerry Curve 8300 and BlackBerry Curve 8310 since March. O2 is very thorough in it's device testing and unfortunatley we have not considered the software to be of good enough quality to allow our customers use it; this is due to various problems with general stability and HTML rendering. O2 values the customer experience above all else and tries it's hardest not to put sub-standard firmware on it's customers devices.
O2 finished testing a version of 4.5 handheld code that we deam to be acceptable for the 8820 about two weeks ago and we will be launching this product next week when we receive stock from RIM. We are now testing the code for the other devices mentioned above and hope to get them into customer's hands in August and September. It takes about a fortnight to test each one on each device and we have limited resource in our device testing team so can't test them all at once. Upon accreditation it takes RIM 2 to 3 weeks to rebundle the code and give it to us to publish.
Unfortunately 4.5 code will not be available for the BlackBerry 8707 and the code we are also currently testing (4.2.2.x) is expected to be the final release for this device. This is due to the Qualcom chipset on this device and the poorer processor. Contrary to what mpob2000 thinks, the 8707 is not a better device than the 8700 - It may have 3G but the Qualcom processor is a greater bottle neck than the EDGE speeds on the 8700 so it's actually slower as a device in most circumstances. It is however better when used as a tethered modem and can also be used in Japan where they only have 3G networks.