Any plan to implement  support for .xlsb files? It's hard to  convince the  customer to use xlsx when xlsb is more efficient.


Sadly we don't have plans to support xlsb, at least for the moment. On one side there is very little demand for it: we've had about 5 requests since it was released back in 2007, and we get dozens of feature requests per week. And on the other side xlsb is a completely different from both xls and xlsx, so it would mean creating a full new engine to add the the 2 we already have: we are speaking about 6 months minimum of developing. We have much more requests for libre/open office support, so if we were to add a new engine, it would be ods.

Now, this is our official reason why we don't support it: The ratio "requests"/"complexity to implement" isn't big enough. But if I might get a little more personal, I'd like to expand more in the topic.

You know, Microsoft releases thousands of technologies that go nowhere. As a small components company, our survival depends in predicting which ones are going to stick and which one won't: if we bet in the wrong techs we are doomed. An example might be silverlight. When sl was released, we got many requests for supporting it in FlexCel for .NET. Looking back now, I am very happy that we didn't (we used the time to create FlexCel 5 for VCL/Firemonkey instead). Another bet we made that wasn't so lucky was supporting pxl (pocket Excel) 1.0 and 2.0: Both FlexCel for .NET and VCL fully support it, and I wonder if anybody uses it today. But once you support a feature you are doomed to support it forever, because you never know if there is people out there still using it and who will be upset if we stopped supporting it. This makes it specially important for us to choose the correct technologies to support.

About what to say to your customers: You are indeed 100% right that xlsb is more efficient. But the de-facto standard right now is xlsx: Microsoft is putting all of its weight there. My personal belief is that xlsb was designed as a "safety net" back in 2006 in case xlsx proved too slow to be used in the real world. But xlsx was "fast enough", even for mobile devices, so xlsb is not really necessary and slowly being forgotten. As computers and phones get faster every year, the need for xlsb decreases even more.  And it won't be the first time ms abandons a file format: They did it last time in 2007 when they deprecated the "Excel 2003 xml" file format introduced in 2003. (and yes, we also got a lot of request back in the time to support excel 2003 xml, and I am also glad we didn't).

So my first question to a customer would be: Is xlsx performance really a problem, or more of a "xlsx is good, but xlsb is faster"?  Second question would be: Do you care about opening the files you are creating now 10 years in the future? 30 years? I am sure you will be able to open xlsx files 30 years from now, as it is the spreadsheet standard today. But xlsb? It might be, it might not be. It is a bet. 

I don't particularly like xlsx, I think it is over-engineered and it is not a nice format. But like it or not, it is the standard today. It has much more momentum, it has the best third party support, and I am almost certain it will outlive xlsb. As an example of third party support, you can look at the documents google docs supports: https://support.google.com/docs/answer/40608?hl=en

And finally the last thing that tells me xlsx is the way going forward: When they started xlsx it had some binary records inside because they hadn't time to convert them. With every new Excel version, those records are replaced by xml counterparts. But in the case of xls or xlsb the contrary is true: They are adding the new features as xlsx blobs inside the binary records. The amount of xml in xls and xlsb is not decreasing with each Excel version, it is getting bigger. To me this is the main indicator they don't care too much about the binary formats.

Any plans for xlsb support?

Sadly the situation is the same as in the previous post on this thread, we see no real demand for xlsb and the effort to support it would be really big. There are just too many things to do and so little time, we need to focus in what most people is expecting.