Including annexes, informative parts, and related standards like IEC 61439 (which might be an updated version) could add value. The user might not know that IEC 60439-1 has been replaced or updated. It would be helpful to mention that and suggest checking for the latest version.
When an old switchboard fails (e.g., arc flash or overheating), investigators must refer to the standard that was valid at the time of manufacture. Using a modern standard for a legacy product is legally incorrect. iec 60439-1 standard pdf
But the industry has moved forward. The old 60439 series has been officially replaced by When an old switchboard fails (e
You're looking for a text related to the IEC 60439-1 standard. Here is some information: The old 60439 series has been officially replaced
If you are transitioning from the old standard, keep these changes in mind as highlighted by experts at GT Engineering Structure:
The most important thing to know about IEC 60439-1 is that it has been withdrawn and replaced by the IEC 61439 series
You have probably hit a wall: the standard is withdrawn, and finding a clean, legal copy is difficult. Here is everything you need to know about this historic standard and where to find it.