diff --git a/requirements/optional.txt b/requirements/optional.txt
index 1d1d84c673..120b4c29d1 100644
--- a/requirements/optional.txt
+++ b/requirements/optional.txt
@@ -8,6 +8,6 @@ iniparse==0.4 ;python_version < '3.0'      # INI (ini2po)
 vobject==0.9.6.1       # iCal (ical2po)
 aeidon==1.2.1 ;python_version > '3.0'      # Subtitles (sub2po)
 l20n==4.0.0a1        # l20n (l20n2po)
-ruamel.yaml==0.15.94 # yaml
+ruamel.yaml==0.15.97 # yaml
 phply==1.2.5         # PHP
 cheroot==6.5.5       # tmserver