It's not in the Rules/Guidelines because it's not necessarily a rule that we enforce (nor is it one that we created).
Asking a developer for an ETA can be seen, by some, as rude because they do the work for free... on their spare time... kind of like us guides and mods. Over the years, some (i.e. not all) developers have taken the stance that asking for an ETA is rude because they have to stop what they are doing to respond that an ETA is unknown so that they can then go back to keep working on developing so that 3 posts later they can go through it again (while if there was a bug reported it would be useful).
So... asking for an ETA is ok, but it's all in the way that it's asked (if that makes sense). The way you asked it, however, seems to be completely fine BTW.
But, to be clear, it is NOT against the rules of the forum (just the unwritten rules of developers mixed with a bit of courtesy (ironic as it may be)).
Feel free to PM me for further clarification or to discuss if needed.
