--- a/Dockerfile	Mon Nov 22 10:40:15 2021 +0000
+++ b/Dockerfile	Mon Nov 22 10:40:32 2021 +0000
@@ -8,6 +8,7 @@
         lua5.2 \
         liblua5.2-dev \
         libidn11-dev \
+        libicu-dev \
         libssl-dev \
         libunbound-dev \
         build-essential \
@@ -15,7 +16,7 @@
 
 WORKDIR /tmp/build
 
-ADD https://hg.prosody.im/trunk/archive/tip.tar.gz ./prosody.tar.gz
+ADD https://hg.prosody.im/trunk/archive/16cf863b36c0.tar.gz ./prosody.tar.gz
 
 RUN tar --strip-components=1 -xzf prosody.tar.gz \
  && ./configure && make