Get:7 http://archive.neon.kde.org/dev/unstable xenial/main Sources [1.549 kB] Err:7 http://archive.neon.kde.org/dev/unstable xenial/main Sources Writing more data than expected (1551971 > 1548600) Fetched 102 kB in 0s (112 kB/s) Reading package lists... Done E: Failed to fetch http://archive.neon.kde.org/dev/unstable/dists/xenial/main/source/Sources Writing more data than expected (1551971 > 1548600)
The CDN is broken. Not much we can do. There's a sysadmin ticket filed about it though.