diff --git a/manifests/swh/apt_config.pp b/manifests/swh/apt_config.pp
index 91b8e1a..4d1055a 100644
--- a/manifests/swh/apt_config.pp
+++ b/manifests/swh/apt_config.pp
@@ -1,71 +1,75 @@
 # Base class for Software Heritage-specific apt configuration
 
 class profile::swh::apt_config {
   $debian_mirror = lookup('swh::apt_config::debian_mirror')
   $debian_security_mirror = lookup('swh::apt_config::debian_security_mirror')
   $debian_enable_non_free = lookup('swh::apt_config::enable_non_free')
 
   class {'::apt':
     purge => {
       'sources.list'   => true,
       'sources.list.d' => false,
       'preferences'    => true,
       'preferences.d'  => true,
     },
   }
 
   package {'apt-transport-https':
     ensure => 'present',
   }
 
   if lookup('swh::apt_config::unattended_upgrades') {
     include profile::swh::apt_config::unattended_upgrades
   }
 
   $repos = $debian_enable_non_free ? {
     true    => 'main contrib non-free',
     default => 'main',
   }
 
   ::apt::source {'debian':
     location => $debian_mirror,
     release  => $::lsbdistcodename,
     repos    => $repos,
   }
 
   ::apt::source {'debian-updates':
     location => $debian_mirror,
     release  => "${::lsbdistcodename}-updates",
     repos    => $repos,
   }
 
   ::apt::source {'debian-security':
     location => $debian_security_mirror,
     release  => "${::lsbdistcodename}/updates",
     repos    => $repos,
   }
 
   if $::lsbdistcodename == 'stretch' {
     class {'::apt::backports':
       pin      => 100,
       location => $debian_mirror,
       repos    => $repos,
     }
+  } else {
+    ::apt::source {'backports':
+      ensure => absent,
+    }
   }
 
   $swh_repository = lookup('swh::apt_config::swh_repository')
   $swh_release = $::lsbdistcodename ? {
     'buster'  => 'sid',
     default   => "${::lsbdistcodename}-swh",
   }
 
   ::apt::source {'softwareheritage':
     comment        => 'Software Heritage specific package repository',
     location       => $swh_repository,
     release        => $swh_release,
     repos          => 'main',
     allow_unsigned => true,
   }
 
   Package['apt-transport-https'] -> Class['apt::update'] -> Package <| title != 'apt-transport-https' |>
 }