Arandr crashes at at launch. Includes error message: "Exception: XRandR 1.2/1.3 required." This worked in F25. Based on https://apps.fedoraproject.org/packages/arandr/overview/ it looks like an older version of Arandr is included in F26 than F25 & updates to F24. This looks like a packaging error.
arandr-0.1.9-2.fc26 has been submitted as an update to Fedora 26. https://bodhi.fedoraproject.org/updates/FEDORA-2017-bc77b98fda
arandr-0.1.9-2.fc26 has been pushed to the Fedora 26 testing repository. If problems still persist, please make note of it in this bug report. See https://fedoraproject.org/wiki/QA:Updates_Testing for instructions on how to install test updates. You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2017-bc77b98fda
arandr-0.1.9-2.fc26 has been pushed to the Fedora 26 stable repository. If problems still persist, please make note of it in this bug report.