diff --git a/docker/Dockerfile b/docker/Dockerfile
index b67779c..571c601 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -20,8 +20,10 @@ RUN apt-get update && apt-get install -y wget
 RUN apt-get update && apt-get install -y lsof dnsutils netcat-openbsd net-tools curl jq python2.7 # used by integration tests
 
 # ruby and jazzy for docs generation
-RUN apt-get update && apt-get install -y ruby ruby-dev libsqlite3-dev
-RUN if [ "${ubuntu_version}" == "focal" ] ; then gem install jazzy --no-document ; fi
+RUN apt-get update && apt-get install -y ruby ruby-dev libsqlite3-dev build-essential
+# jazzy no longer works on xenial as ruby is too old.
+RUN if [ "${ubuntu_version}" = "focal" ] ; then echo "gem: --no-document" > ~/.gemrc; fi
+RUN if [ "${ubuntu_version}" = "focal" ] ; then gem install jazzy; fi
 
 # cmake build
 RUN apt-get update && apt-get install -y cmake ninja-build
diff --git a/scripts/generate_docs.sh b/scripts/generate_docs.sh
index ea8a101..2313186 100755
--- a/scripts/generate_docs.sh
+++ b/scripts/generate_docs.sh
@@ -31,7 +31,7 @@ if [[ "$(uname -s)" == "Linux" ]]; then
   if [[ ! -d "$source_kitten_source_path" ]]; then
     git clone https://github.com/jpsim/SourceKitten.git "$source_kitten_source_path"
   fi
-  source_kitten_path="$source_kitten_source_path/.build/x86_64-unknown-linux/debug"
+  source_kitten_path="$source_kitten_source_path/.build/debug"
   if [[ ! -d "$source_kitten_path" ]]; then
     rm -rf "$source_kitten_source_path/.swift-version"
     cd "$source_kitten_source_path" && swift build && cd "$root_path"
@@ -39,7 +39,7 @@ if [[ "$(uname -s)" == "Linux" ]]; then
   # generate
   for module in "${modules[@]}"; do
     if [[ ! -f "$root_path/.build/sourcekitten/$module.json" ]]; then
-      "$source_kitten_path/sourcekitten" doc --spm-module $module > "$root_path/.build/sourcekitten/$module.json"
+      "$source_kitten_path/sourcekitten" doc --spm --module-name $module > "$root_path/.build/sourcekitten/$module.json"
     fi
   done
 fi