Now that RIM has completed the BIS 2.5 upgrade, the chore of rolling out the BlackBerry 4.5 OS to a variety of devices can start. The 4.5 OS upgrade will be available for the 8100, 8800, 8820, 8300, 8310, 8120, 8110 and 8700. If a BlackBerry launches prior to September it will have the 4.5 version of the OS.

One thing that is absent from this list are the CDMA versions of the BlackBerry. According to what we are hearing, the CDMA BlackBerry devices in the same family will be getting OS 4.5 as well, but it is possible that the time frame may be a bit later than the GSM versions.

The key news here is that the major rollout will start for devices that don’t have the 4.5 OS in September. According to our sources, some users will not be waiting until September, for example, Vodafone customers already have it; so perhaps what RIM is saying is that they are hoping to have all carriers rolling out 4.5 of the OS by September. Still, according to our moles, the availability of the 4.5 OS will still be up to the carrier.

The biggest news of the 4.5 upgrade that will have a direct impact on end users is the addition of native HTML support in E-mail. In addition, the ability to handle attachments as large as 3MB has been expanded. Push E-mail support for Hotmail/MSN and AOL accounts has also been included in the 4.5 OS upgrade.

So far, the buzz surrounding the 4.5 OS upgrade has been very positive and many users are looking forward to the 4.5 OS upgrade. It is a shame that we will have to wait for September for it to start rolling out in most cases.