Ubuntu seems to be having an issue with the deb packages. On 16.04, it complains about the "Valid-Until" entry in the Release file, and on 16.10 it complains about the "Date" entry and the security. Here are the error messages from 16.04:
W: http://dev.monetdb.org/downloads/deb/dists/xenial/Release.gpg: Signature by key 213E64DCD5DDC2C063CC39FD053C3ED40583366F uses weak digest algorithm (SHA1) W: Invalid 'Date' entry in Release file /var/lib/apt/lists/dev.monetdb.org_downloads_deb_dists_xenial_Release W: http://www.openprinting.org/download/printdriver/debian/dists/lsb3.2/Release...: Signature by key F8897B6F00075648E248B7EC24CBF5474CFD1E2F uses weak digest algorithm (SHA1) E: Failed to fetch http://dev.monetdb.org/downloads/deb/dists/xenial/Release Invalid 'Valid-Until' entry in Release file /var/lib/apt/lists/dev.monetdb.org_downloads_deb_dists_xenial_Release
And from 16.10:
W: http://dev.monetdb.org/downloads/deb/dists/yakkety/Release.gpg: Signature by key 213E64DCD5DDC2C063CC39FD053C3ED40583366F uses weak digest algorithm (SHA1) W: Invalid 'Date' entry in Release file /var/lib/apt/lists/partial/dev.monetdb.org_downloads_deb_dists_yakkety_Release E: The repository 'http://dev.monetdb.org/downloads/deb yakkety Release' provides only weak security information. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.
I know the workarounds to get it working on my machine, I just wanted to put this issue out there in case it started with the recent release.
-CAD