diff --git a/Dockerfile b/Dockerfile
index 84d95a2..6d30185 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -28,7 +28,7 @@ apt-get -y --no-install-recommends install \
 apt-get -y clean && \
 rm -rf /var/lib/apt/lists/* && \
 wget https://download.brother.com/welcome/dlf105200/brscan4-0.4.11-1.amd64.deb --progress=dot:giga -O /tmp/brscan4.deb && \
-wget https://download.brother.com/welcome/dlf006652/brscan-skey-0.3.2-0.amd64.deb --progress=dot:giga -O /tmp/brscan-skey.deb && \
+wget https://download.brother.com/welcome/dlf006652/brscan-skey-0.3.5-0.amd64.deb --progress=dot:giga -O /tmp/brscan-skey.deb && \
 dpkg -i --force-all /tmp/brscan4.deb && \
 dpkg -i --force-all /tmp/brscan-skey.deb && \
 rm -f /tmp/brscan4.deb /tmp/brscan-skey.deb
diff --git a/script/scanRear.sh b/script/scanRear.sh
index 3fa0180..e1eb031 100755
--- a/script/scanRear.sh
+++ b/script/scanRear.sh
@@ -30,8 +30,13 @@ output_pdf_file="/scans/${date}.pdf"
 
 cd "$tmp_dir"
 
-kill -9 "$(cat scan_pid)"
-rm scan_pid
+if [ -f scan_pid ]; then
+  pid=$(cat scan_pid)
+  if [ -n "$pid" ] && kill -0 "$pid" 2>/dev/null; then
+    kill -9 "$pid"
+  fi
+  rm -f scan_pid
+fi
 
 function scan_cmd() {
   # `brother4:net1;dev0` device name gets passed to scanimage, which it refuses as an invalid device name for some reason.