diff --git a/CHANGELOG.md b/CHANGELOG.md
index 710a4093..947af670 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -26,6 +26,7 @@ The **patch** part changes incrementally at each release.
 * apt: store keys in /etc/apt/trusted.gpg.d in ascii format
 * certbot: sync_remote.sh is configurable
 * evolinux-base: copy GPG key instead of using apt-key
+* evomaintenance: upstream release 0.6.4
 * kvm-host: replace the "kvm-tools" package with scripts deployed by Ansible
 * nodejs: change GPG key name
 * ntpd: Add leapfile configuration setting to ntpd on debian 10+
diff --git a/evomaintenance/files/evomaintenance.sh b/evomaintenance/files/evomaintenance.sh
index 1cd4ce7f..1961ebf2 100644
--- a/evomaintenance/files/evomaintenance.sh
+++ b/evomaintenance/files/evomaintenance.sh
@@ -4,16 +4,16 @@
 # Dependencies (all OS): git postgresql-client
 # Dependencies (Debian): sudo
 
-# Copyright 2007-2019 Evolix <info@evolix.fr>, Gregory Colpart <reg@evolix.fr>,
+# Copyright 2007-2021 Evolix <info@evolix.fr>, Gregory Colpart <reg@evolix.fr>,
 #                     Jérémy Lecour <jlecour@evolix.fr> and others.
 
-VERSION="0.6.3"
+VERSION="0.6.4"
 
 show_version() {
     cat <<END
 evomaintenance version ${VERSION}
 
-Copyright 2007-2019 Evolix <info@evolix.fr>,
+Copyright 2007-2021 Evolix <info@evolix.fr>,
                     Gregory Colpart <reg@evolix.fr>,
                     Jérémy Lecour <jlecour@evolix.fr>
                     and others.
@@ -178,9 +178,11 @@ is_repository_readonly() {
     if [ "$(get_system)" = "OpenBSD" ]; then
         partition=$(stat -f '%Sd' $1)
         mount | grep ${partition} | grep -q "read-only"
-    else
+    elif command -v findmnt >/dev/null; then
         mountpoint=$(stat -c '%m' $1)
         findmnt ${mountpoint} --noheadings --output OPTIONS -O ro
+    else
+        grep /usr /proc/mounts | grep -E '\bro\b'
     fi
 }
 remount_repository_readwrite() {