However, one annoying side-effect for me is I immediately started receiving SMS notifications which were blank (or just said "SMS message") and displayed the location I was in (for example my suburb or nearby suburbs). Each message came with the option to "save" or "cancel". If I selected 'cancel' it would just go away. If I select save, it appears in my text messages coming from the sender '50'.
The annoying part is that these messages just kept coming. As I move my phone around the house it would every minute or so get messages from the sender "50" and give me an annoying notification that I had to respond to.
It turns out that these messages appear to be "Cell Broadcast" messages. The cell broadcast forum states that:
Cell Broadcast (CB) is a mobile technology that allows messages (currently of up to 15 pages of up to 93 characters) to be broadcast to all mobile handsets and similar devices within a designated geographical area. The broadcast range can be varied, from a single cell to the entire network.
There's more information about it at Wikipedia - Cell Broadcast.
In any case, it seems that the update to Android 2.3.5 and HTC Sense 3.0 on the HTC phone has caused it to start notifying me of each Cell Broadcast messages coming from channel 50. (Presuming they didn't just start broadcasting in my area this morning at the exact time I did my update, at least!)
Solution: I decided I would leave Cell Broadcasts generally enabled on the phone, but simply disable this channel.
To do this, you go to Settings on your Android phone. Then select Call. In this menu you have the option to enable or disable "Cell broadcast". I left it enabled and clicked on the "Cell broadcast settings" option, further down the list. Here I found the broadcast channel causing the problems (50) and clicked on it to select "disable".
This fixed the problem and my phone is back to its normal, quiet self! I guess I could have disabled "Cell Broadcast" entirely, but, who knows? One day there may be a flood coming to my area and I'll be glad I left it on!
I couldn't find anything about this specific issue on the internet, so thought I'd record this for others who experience the same problem. I'd be interested in comments if others know more about this and there is a better way to handle it. Was it just me, or are others are also experiencing this problem?