«"Keeping the controller (PLC/DCS) firmware up to date can significantly reduce your network's threat vectors by decreasing the percentage of devices with exploitable vulnerabilities.".
I saw this on a website specializing in Automation; however, at least in my experience, this does not always apply and is sometimes not recommended.
I repeat, at least in my experience, I have seen how a new firmware becomes available that, in theory, provides better performance or closes security gaps, but I have also seen how on certain occasions they bring incompatibilities with the PLC or DCS system that is already working, and worse still, they bring "more problems" than the "problems they solve".
Of course, it's always advisable to keep the firmware updated; however, in my opinion, we should review the changes between versions and analyze whether these changes are always positive or if, on the contrary, they could impact system availability. We should ask ourselves: Will these changes actually bring benefits? Or, on the contrary, could there be any problems?
Another thing I've noticed is that when a real problem arises for many PLC/DCS customers, the manufacturer rushes to release a new firmware update to fix it. A few weeks later, the new firmware is released and everything seems great. However, perhaps due to the pressure of speed, other related problems start to appear, and again, a few weeks later, the manufacturer releases another update with the "final" solution. Perhaps some of you have experienced this.
In conclusion, my humble recommendation is to keep track of changes in available firmware versions, analyze whether this update is truly necessary or will add value; otherwise, it might be better to "skip" this version and wait for the next one (in this latter case) you save yourself a little time of "unavailable" system.«
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