diff --git a/.github/workflows/linux.yml b/.github/workflows/linux.yml
index cb4da433..45ff83fe 100644
--- a/.github/workflows/linux.yml
+++ b/.github/workflows/linux.yml
@@ -112,7 +112,7 @@ jobs:
             build-type: release
 
           # openSUSE's release cycle: https://endoflife.date/opensuse
-          - image: opensuse-15_5
+          - image: opensuse-15_6
             build-script: rpm_entrypoint.sh
             build-type: release
     steps:
diff --git a/Dockerfiles/opensuse-15_5 b/Dockerfiles/opensuse-15_6
similarity index 84%
rename from Dockerfiles/opensuse-15_5
rename to Dockerfiles/opensuse-15_6
index 7e915353..c55d91ed 100644
--- a/Dockerfiles/opensuse-15_5
+++ b/Dockerfiles/opensuse-15_6
@@ -1,7 +1,7 @@
 # vim: set syntax=dockerfile:
-FROM opensuse/leap:15.5
+FROM opensuse/leap:15.6
 
-LABEL org.opencontainers.image.description="Base image used to build and RPM-package Notes on openSUSE 15.5"
+LABEL org.opencontainers.image.description="Base image used to build and RPM-package Notes on openSUSE 15.6"
 
 # Install dependencies.
 RUN zypper install -y --no-recommends cmake gcc10-c++ git \
@@ -12,6 +12,9 @@ RUN zypper install -y --no-recommends cmake gcc10-c++ git \
 ENV CC=gcc-10
 ENV CXX=g++-10
 
+# Silences locale-related warnings from AutoUic.
+ENV LANG=C.UTF-8
+
 # Prevent a fatal error from git: "detected dubious ownership in repository at '/src'".
 RUN git config --global --add safe.directory /src