diff --git a/etc/apt/sources.list/.devel.I.do.not.update.this b/etc/apt/sources.list/.devel.I.do.not.update.this
deleted file mode 100644
index 721b41ff..00000000
--- a/etc/apt/sources.list/.devel.I.do.not.update.this
+++ /dev/null
@@ -1,31 +0,0 @@
-## Main repositories
-deb mirror://mirrors.ubuntu.com/mirrors.txt devel main restricted universe multiverse
-deb-src mirror://mirrors.ubuntu.com/mirrors.txt devel main restricted universe multiverse
-deb mirror://mirrors.ubuntu.com/mirrors.txt devel-updates main restricted universe multiverse
-deb-src mirror://mirrors.ubuntu.com/mirrors.txt devel-updates main restricted universe multiverse
-deb mirror://mirrors.ubuntu.com/mirrors.txt devel-security main restricted universe multiverse
-deb-src mirror://mirrors.ubuntu.com/mirrors.txt devel-security main restricted universe multiverse
-deb http://security.ubuntu.com/ubuntu devel-security main restricted universe multiverse
-deb-src http://security.ubuntu.com/ubuntu devel-security main restricted universe multiverse
-
-## Backports
-## https://help.ubuntu.com/community/UbuntuBackports
-deb mirror://mirrors.ubuntu.com/mirrors.txt devel-backports main restricted universe multiverse
-deb-src mirror://mirrors.ubuntu.com/mirrors.txt devel-backports main restricted universe multiverse
-
-## Pre-release updates
-## https://wiki.ubuntu.com/Testing/EnableProposed
-#deb mirror://mirrors.ubuntu.com/mirrors.txt devel-proposed main restricted universe multiverse
-#deb-src mirror://mirrors.ubuntu.com/mirrors.txt devel-proposed main restricted universe multiverse
-
-## Proprietary and closed-source software
-deb http://archive.canonical.com/ubuntu devel partner
-deb-src http://archive.canonical.com/ubuntu devel partner
-
-## Non-built-in debug symbol packages
-## https://wiki.ubuntu.com/DebuggingProgramCrash
-## sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 428D7C01
-#deb http://ddebs.ubuntu.com devel main restricted universe multiverse
-#deb http://ddebs.ubuntu.com devel-updates main restricted universe multiverse
-## Ignore unless you have enabled proposed
-#deb http://ddebs.ubuntu.com devel-proposed main restricted universe multiverse
diff --git a/etc/apt/sources.list/14.04 b/etc/apt/sources.list/14.04
index 8b067e34..5b5cf5a2 100644
--- a/etc/apt/sources.list/14.04
+++ b/etc/apt/sources.list/14.04
@@ -28,13 +28,13 @@ deb-src http://extras.ubuntu.com/ubuntu trusty main
 
 ## Non-built-in debug symbol packages
 ## https://wiki.ubuntu.com/DebuggingProgramCrash
-## sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 428D7C01
+## sudo apt-key adv --keyserver hkps://keys.openpgp.org --recv-keys 428D7C01
 #deb http://ddebs.ubuntu.com trusty main restricted universe multiverse
 #deb http://ddebs.ubuntu.com trusty-updates main restricted universe multiverse
 ## Ignore unless you have enabled proposed
 #deb http://ddebs.ubuntu.com trusty-proposed main restricted universe multiverse
 
 ## Ubuntu MATE
-## apt-key adv --keyserver pool.sks-keyservers.net --recv-keys 709A860A600B9A61FEF5346AFB01CC26162506E7
+## apt-key adv --keyserver hkps://keys.openpgp.org --recv-keys 709A860A600B9A61FEF5346AFB01CC26162506E7
 #deb http://ppa.launchpad.net/ubuntu-mate-dev/trusty-mate/ubuntu trusty main
 #deb-src http://ppa.launchpad.net/ubuntu-mate-dev/trusty-mate/ubuntu trusty main
diff --git a/etc/apt/sources.list/16.04 b/etc/apt/sources.list/16.04
index c5a1bb62..1c24b726 100644
--- a/etc/apt/sources.list/16.04
+++ b/etc/apt/sources.list/16.04
@@ -24,13 +24,13 @@ deb-src http://archive.canonical.com/ubuntu xenial partner
 
 ## Non-built-in debug symbol packages
 ## https://wiki.ubuntu.com/DebuggingProgramCrash
-## sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 428D7C01
+## sudo apt-key adv --keyserver hkps://keys.openpgp.org --recv-keys 428D7C01
 #deb http://ddebs.ubuntu.com xenial main restricted universe multiverse
 #deb http://ddebs.ubuntu.com xenial-updates main restricted universe multiverse
 ## Ignore unless you have enabled proposed
 #deb http://ddebs.ubuntu.com xenial-proposed main restricted universe multiverse
 
 ## Ubuntu MATE
-## apt-key adv --keyserver pool.sks-keyservers.net --recv-keys 709A860A600B9A61FEF5346AFB01CC26162506E7
+## apt-key adv --keyserver hkps://keys.openpgp.org --recv-keys 709A860A600B9A61FEF5346AFB01CC26162506E7
 #deb http://ppa.launchpad.net/ubuntu-mate-dev/xenial-mate/ubuntu xenial main
 #deb-src http://ppa.launchpad.net/ubuntu-mate-dev/xenial-mate/ubuntu xenial main
diff --git a/etc/apt/sources.list/18.04 b/etc/apt/sources.list/18.04
index b1eba2dc..a3e2aa84 100644
--- a/etc/apt/sources.list/18.04
+++ b/etc/apt/sources.list/18.04
@@ -24,13 +24,13 @@ deb-src http://archive.canonical.com/ubuntu bionic partner
 
 ## Non-built-in debug symbol packages
 ## https://wiki.ubuntu.com/DebuggingProgramCrash
-## sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 428D7C01
+## sudo apt-key adv --keyserver hkps://keys.openpgp.org --recv-keys 428D7C01
 #deb http://ddebs.ubuntu.com bionic main restricted universe multiverse
 #deb http://ddebs.ubuntu.com bionic-updates main restricted universe multiverse
 ## Ignore unless you have enabled proposed
 #deb http://ddebs.ubuntu.com bionic-proposed main restricted universe multiverse
 
 ## Ubuntu MATE
-## apt-key adv --keyserver pool.sks-keyservers.net --recv-keys 709A860A600B9A61FEF5346AFB01CC26162506E7
+## apt-key adv --keyserver hkps://keys.openpgp.org --recv-keys 709A860A600B9A61FEF5346AFB01CC26162506E7
 #deb http://ppa.launchpad.net/ubuntu-mate-dev/bionic-mate/ubuntu bionic main
 #deb-src http://ppa.launchpad.net/ubuntu-mate-dev/bionic-mate/ubuntu bionic main