Windows 10 Mobile was update was suspended on Lumia 950 and 950 Xl due to several glitches, but now the update is back online and ready to download.
Microsoft published a statement:
"After momentarily pausing the Windows 10 Mobile update due to an issue with the update server that impacted the installation of the update on a limited number of phones, we have addressed the issue and will begin rolling out the 10586.29 update again."