I'm trying to open an InDesign file (created by someone else) but I get this message: "Cannot open "1.1.indd". Please upgrade your plug-ins to their latest versions, or upgrade to the latest version of Adobe InDesign".
I should say that I'm working with CS4 ME and the file ("1.1") is part of a series in which some of the files open and some don't.
the file was saved in a newer version of ID. You will need to upgrade, or ask for a .idml file (and a PDF so you know what it should look like).
This can help you identify waht version was last used to edit the file: Adobe Forums: [Ann] Identify Your InDesign File
Thank you for your answer. Just - what is a .idml file? Also: I didn't understand how to use Jongware's suggestion. I asked that question in the thread in your link.
IDML is InDesign's interchange format for older versions.