Build 3.5.0.121 of xlsgen ensures that in-memory scenarios preserve the internal XLSM mime type, avoiding a prompt whenever the files are opened in Excel.

When Excel 2007 introduced XLSM files for "macros", it actually introduced a subtle marking of the file, most probably for screening purposes, as such. In-memory scenarios in xlsgen lacked this capability so far because the algorithm was based on the file extension, XLSX versus XLSM, and there is no such thing as a file extension in in-memory scenarios.

So beginning with this build, xlsgen reads the internal markers of input buffers to figure out these are meant to be "macro enabled" output buffers. This is completely transparent for the client application, and for Excel.