The risk of firmware updates from manufacturers is non-negligible (to them QA is a word on a label you stick on all of your products). The benefit appears to be questionable.
Strange, I have done lots of firmware updates on various devices, and while there was the occasional lemon amongst them the majority has proven to be beneficial.
Firmware updates may also be designed to work with new hardware revisions
Yes, but then they are flashed directly into production units and not offered for download or sent out to customers.
or solve problems you never had in the first place. Or they may remove features because a competitor filed a patent claim. Without a changelog it's hard to tell.
I agree a changelog would be nice. But there's nothing wrong with testing a new firmware and going back to the previous version if really necessary. At the end of the day, we're talking about a cheap Chinese-made device which has it's fair share of issues as most devices in this class. If you require changelogs and tested firmware then you should buy the much more expensive variant from LeCroy.
So they fixed a bug related to dBm output levels. Unless you actually use this feature, it may be better to wait for the next update. Unless you consider the enjoyment of updating firmware important enough to risk the possible problems.
One of the bugs fixed is the dBm bug. There may be others but without changelog we won't find out. There may also be new issues but if no-one tries the firmware we won't find out as well. If your livelihood depends on a working Siglent AWG then I agree flashing new firmware may be too risky (but then you should really think about buying some proper gear with appropriate support contracts). For the rest of us who use this thing as a hobby device or have more than one AWG there's no reason why we can't try a new firmware.
And why should one wait for the next update?
Even firmware updates from reputable manufacturers occasionally cause problems: a Gossen Metrahit Energy update wiped out the calibration constants, requiring a trip to Gossen or a cal lab.
Yes, even reputable manufacturers can sometimes put up a lemon firmware (even when in my experience failed firmware updates are much more often caused by a non-obvious problem with the device that's flashed.). The majority of updates however are not causing problems and work as designed.
Saying not to flash new firmware updates because they might cause problems is the same as saying you should never buy electronic devices as they might be DOA.
And again, you should consider what device we're talking about, and in what environment such devices are generally used.