Excel Uses New Files for Chart Styles and Colors

[oleibman]

Until recently, Excel has generated all the data for a chart using a single xml file, e.g. chart1.xml. It has now taken to generating 2 extra files (e.g. style1.xml and colors1.xml). The chart directory now has a rels directory with entries for each of the charts, e.g. chart1.xml.rels, with rid entries for the new files. PhpSpreadsheet does not know how to deal with the new files. This is especially true since chart1.xml does not actually use any of the rid's in the rels file, but, even if it did, there would still be a lot of work involved. Although spreadsheets with the new chart files will continue to be loadable, we can certainly anticipate that there will be reports of problems with styling and coloring of charts in future.

[oleibman]

"New" seems relative. It appears that the 2 extra files date back to at least Excel 2013. They were not present in Excel 2007. I don't have access to a version of Excel 2010, so don't know its behavior. At any rate, since they've been available since at least 2013, I am at least reassured that there's not going to be a deluge of new problem reports.