Recently, in the field of jailbreaking so much activity that it is difficult to follow all the news. Constantly go out and announce new tools that support various devices with different firmware.
Update Cydia and Substrate for iOS 11

However, one thing we know for sure - upgrading Cydia and Substrate with support for iOS 11 has still failed. For now. Soon this may change.
Jay Freeman, the creator of Cydia, already wrote that he was going to release an update with support for iOS 11. Of course, he did not tell any exact dates, like other reliable sources.
However, we take the risk that the Cydia update will be released very soon.
Earlier, Jay Freeman admitted that he was working with his old team. If you go to http://apt.saurik.com, you will see that the date of the debs folder changed from 2017 to January 4, 2018. This file has not changed for a long time until this point. Perhaps some changes have already been made, and they relate to the Cydia and Substrate updates for iOS 11.
For now, these are just assumptions, and they do not mean anything. However, we have waited so much time for updates to be released, which is even encouraging for the slightest hope. As usual, you just have to wait. We will tell you if there is any news.