This post is not directly related to the new release (I have yet to install the update), but I wanted to write a few words and say
thank you to those who maintain and contribute to Sigil. I hope it's ok to do it here rather than starting a separate thread.
I published my first e-book (EPUB 3) last year with the help of Sigil. I experienced a couple of issues/bugs, which were later fixed by the developers. If Sigil was a paid application, I would say that the support is great. But it's free, and the developers don't even accept donations. The support and dedication of Sigil's highly knowledgeable developers is simply outstanding! I and other users should consider ourselves very lucky to be able to use a free program that is so well developed and maintained by
DiapDealer and
KevinH, with help from
BeckyEbook and others.
If a user has a feature request or report a potential issue, the developers seem quick to reply. Even if they think that a specific problem is user error or caused by a poorly-coded imported file, they still investigate it. And yes, if someone has a "silly" feature request or complains about an issue that is clearly user error, the developers will give it to him/her straight

That's fine.
If a genuine bug is found, the developers dig deeper and fix it. Even if it's not technically a bug, they sometimes spend a lot of time looking for ways to improve Sigil, so that we end up with software that is more robust and feature-rich. I'm seriously impressed, because I know that this can be very time-consuming work. Even checking this forum and replying to users must take a lot of time. From what I've seen, the developers really go above and beyond!
My background and experience with Sigil
I have published many books (popular science) in the last 20 years. Several of them have been self-published. For personal reasons I'm no longer able to handle the workload and logistics of paper books. My recent book has therefore been published as an e-book using Sigil. As expected, the sales figure is pathetic compared to the previous paper editions, but this has nothing to do with Sigil.
I have basic HTML and coding skills, and since I read the manual several times before even installing Sigil, I didn't have too much trouble producing the e-book. I tried keeping it simple. I added basic formatting and more than 200 images plus quite a few lists and a few tables. Because I want users to be able to read the book on their smartphone, I reduced the number of tables – and the number of columns in them – to an absolute minimum. On an iPad Mini, the total number of pages is 400–500 (depending on the font size). Luckily, I had no problem getting my file validated with the EpubCheck plugin. Thank you,
Doitsu, for the plugin!
Two minor annoyances are
1) that all undo history is lost after saving, and
2) very high memory/RAM use after minimizing Sigil to the Dock and restoring it on my Intel 5K iMac (approaching 9 GB with a small file containing only a few lines of text). Both have been discussed in the forum, and I can certainly live with these minor issues.
Sigil does everything I need – and a heck of a lot more.
Thanks again to all developers and contributors!