If it's working now it's unlikely that the later firmware that will take functionality away, however:
-Official support for SDHC + MEAD-SD01 adaptor (as well as Memory Stick + MEAD-MS01) was added in 1.20.
-Sony strongly recommends you use SxS media and recommends SD/MS "for emergency use only." This is not simply a ploy to get users to adopt the more expensive Sony media. If you have a failure or any kind of data problem with SxS, there are a number of Sony resources available to you. If you have a problem with SDHC cards the issues can be infinitely more painful and time consuming to sort out. We also have strict controls over the type and quality of memory used in SxS, as well as the electrical interface and the controller. The failure rate of SxS is very low when used properly; the failure rate of SDHC cards is much higher.
Not trying to scare anyone but these are the facts. Obviously if SDHC were too risky Sony wouldn't support it at all, but in certain areas it pays to be a bit more conservative.
-EX1s running firmware below 1.13 need to be updated by Sony. After 1.13 you can use the Version Up tool to upgrade the hardware yourself. There has been some confusion and a recent change in policy concerning this (used to be 1.11) but this is the current upgrade path.
I'll check out my EX1 to see what firmware I have (I guess this is just found by searching the menu?).
I did have a problem with a 32GB SxS card, but unfortunately Sony were less than helpful. This gave me little encouragement to continue to use SxS cards. I believe this was caused by our camera not having a adequately high enough firmware version to use 32GB cards.
I think I will upgrade the firmware on the EX1 - just didn't want to cause any problems. If it is not broken and all that!
On the note of using SxS cards. I agree that the failure rate is probably higher with SDHC cards, but on Sony's site, they play this down quite a bit. Or at least the way I read it:
"The nature of the adaptor and Memory Stick media will also mean slightly less reliability than SxS media"