diff --git a/programs/pdf2pdfa b/programs/pdf2pdfa
index 084614b..33b5f58 100755
--- a/programs/pdf2pdfa
+++ b/programs/pdf2pdfa
@@ -7,6 +7,7 @@ OUTPUT=$2
 DPI=$3
 MAXBITMAP=$4
 PDFSETTINGS=$5
+PDFA_CONFORMANCE=$6
 
 if [ -z "$DPI" ]; then
   DPI=720
@@ -43,6 +44,16 @@ if ! [[ $MAXBITMAP =~ $re ]] ; then
   exit 2
 fi
 
+PDFA_CONFORMANCE_NUM=""
+if [[ ! $PDFA_CONFORMANCE =~ $re ]] || [[ "$PDFA_CONFORMANCE" -lt 1 ]] || [[ "$PDFA_CONFORMANCE" -gt 3 ]]; then
+  echo "error: PDFA_CONFORMANCE invalid - only values from 1 to 3 are allowed"
+  exit 2
+fi
+if [ -n "$PDFA_CONFORMANCE" ] && [ "$PDFA_CONFORMANCE" -gt 1 ]; then
+  # The ghostscript documentation specifies that -dPDFA parameter should only have the version value followed when using 2 or 3
+  PDFA_CONFORMANCE_NUM="=$PDFA_CONFORMANCE"
+fi
+
 docker run \
   --runtime="${LAUNDRY_DOCKER_RUNTIME:-runsc}" \
   --network=none \
@@ -53,5 +64,5 @@ docker run \
   --rm \
   laundry-programs \
     /bin/bash -c 'cat > /home/docconv/document.pdf && \
-    gs -q -dPDFA -dBATCH -dNOPAUSE -r'$DPI' -dMaxBitmap='$MAXBITMAP' '$PDFSETTINGS' -sProcessColorModel=DeviceCMYK -sDEVICE=pdfwrite -dPDFACompatibilityPolicy=1 -sOutputFile=- /home/docconv/document.pdf' \
+    gs -q -dPDFA'$PDFA_CONFORMANCE_NUM' -dBATCH -dNOPAUSE -r'$DPI' -dMaxBitmap='$MAXBITMAP' '$PDFSETTINGS' -sProcessColorModel=DeviceCMYK -sDEVICE=pdfwrite -dPDFACompatibilityPolicy=1 -sOutputFile=- /home/docconv/document.pdf' \
     < "$INPUT" > "$OUTPUT"
diff --git a/resources/public/index.html b/resources/public/index.html
index a75d6ac..65d42b7 100644
--- a/resources/public/index.html
+++ b/resources/public/index.html
@@ -9,7 +9,8 @@
   var pdfParameters = [
     {"type": "pdf/pdf2pdfa", key: "dpi", dtype: "number", wrapper: "pdf_dpi_elem", elem: "pdf_dpi" },
     {"type": "pdf/pdf2pdfa", key: "maxbitmap", dtype: "number", wrapper: "pdf_maxbitmap_elem", elem: "pdf_maxbitmap" },
-    {"type": "pdf/pdf2pdfa", key: "pdfsettings", wrapper: "pdf_pdfsettings_elem", elem: "pdf_pdfsettings" }
+    {"type": "pdf/pdf2pdfa", key: "pdfsettings", wrapper: "pdf_pdfsettings_elem", elem: "pdf_pdfsettings" },
+    {"type": "pdf/pdf2pdfa", key: "pdfaconformance", dtype: "number", wrapper: "pdf_pdfaconformance_elem", elem: "pdf_pdfaconformance" }
   ]
 
   function updateConversionParameters() {
@@ -104,6 +105,9 @@ <h1>Laundry</h1>
    <div id="pdf_pdfsettings_elem">
      <input type="text" id="pdf_pdfsettings" name="pdfsettings" value="/default"> Pdfsettings
    </div>
+   <div id="pdf_pdfaconformance_elem">
+     <input type="number" id="pdf_pdfaconformance" name="pdfaconformance" value="1"> Pdf/a conformance (Valid values: 1-3)
+   </div>
    <form id="pdfop">
    <input type="file" name="file">
    <input type="button" value="Convert" onclick="pdfConverter()">
diff --git a/src/laundry/pdf.clj b/src/laundry/pdf.clj
index 21c7cd7..eb14a48 100644
--- a/src/laundry/pdf.clj
+++ b/src/laundry/pdf.clj
@@ -17,21 +17,28 @@
         (proxy-super close)
         (io/delete-file path)))))
 
+(s/defn validate-pdf-settings [pdfsettings :- s/Str]
+  (when-not (#{"/screen" "/ebook" "/printer" "/prepress" "/default"} pdfsettings) "pdfsettings is not given in correct format"))
+
 ;; pdf/a converter
-(s/defn api-pdf2pdfa [env, tempfile :- java.io.File, dpinum :- s/Int, maxbitmapnum :- s/Int, pdfsettings :- s/Str]
-  (let [in-path (.getAbsolutePath tempfile)
-        out-path  (str (.getAbsolutePath tempfile) ".pdf")
-        dpi (str dpinum)
-        maxbitmap (str maxbitmapnum)
-        pdfsettings (str pdfsettings)
-        res (shell-out! (str (:tools env) "/pdf2pdfa")
-                        in-path out-path dpi maxbitmap pdfsettings)]
-    (.delete tempfile)
-    (if (= (:exit res) 0)
-      (htresp/content-type
-       (htresp/ok (temp-file-input-stream out-path))
-       "application/pdf")
-      (badness-resp "pdf2pdfa conversion failed" res))))
+(s/defn api-pdf2pdfa [env, tempfile :- java.io.File, dpinum :- s/Int, maxbitmapnum :- s/Int, pdfsettings :- s/Str, pdfaconformancenum :- s/Int]
+  (if-let [pdfsettings-error (validate-pdf-settings (str pdfsettings))] 
+    (badness-resp pdfsettings-error pdfsettings-error)
+
+    (let [in-path (.getAbsolutePath tempfile)
+          out-path  (str (.getAbsolutePath tempfile) ".pdf")
+          dpi (str dpinum)
+          maxbitmap (str maxbitmapnum)
+          pdfsettings (str pdfsettings)
+          pdfaconformance (str pdfaconformancenum)
+          res (shell-out! (str (:tools env) "/pdf2pdfa")
+                          in-path out-path dpi maxbitmap pdfsettings pdfaconformance)]
+      (.delete tempfile)
+      (if (= (:exit res) 0)
+        (htresp/content-type
+         (htresp/ok (temp-file-input-stream out-path))
+         "application/pdf")
+        (badness-resp "pdf2pdfa conversion failed" res)))))
 
 ;; pdf → txt conversion
 (s/defn api-pdf2txt [env, tempfile :- java.io.File]
@@ -80,11 +87,11 @@
          (api-pdf2txt env tempfile)))
      (POST "/pdf2pdfa" []
        :summary "attempt to convert a PDF file to PDF/A"
-       :query-params #_{:clj-kondo/ignore [:unresolved-symbol]} [{dpi :- s/Int 720} {maxbitmap :- s/Int 0} {pdfsettings :- s/Str "/default"}]
+       :query-params #_{:clj-kondo/ignore [:unresolved-symbol]} [{dpi :- s/Int 720} {maxbitmap :- s/Int 0} {pdfsettings :- s/Str "/default"} {pdfaconformance :- s/Int 1}]
        :multipart-params [file :- upload/TempFileUpload]
        :middleware [wrap-multipart-params]
        (let [tempfile (:tempfile file)
              filename (:filename file)]
          (info "PDF converter received " filename "(" (:size file) "b)")
          (.deleteOnExit tempfile) ;; cleanup if VM is terminated
-         (api-pdf2pdfa env tempfile dpi maxbitmap pdfsettings))))))
+         (api-pdf2pdfa env tempfile dpi maxbitmap pdfsettings pdfaconformance))))))
diff --git a/test/laundry/pdf_test.clj b/test/laundry/pdf_test.clj
index bd47473..fc09f2f 100644
--- a/test/laundry/pdf_test.clj
+++ b/test/laundry/pdf_test.clj
@@ -47,6 +47,7 @@
                     (assoc-in [:query-params :dpi] 720)
                     (assoc-in [:query-params :maxbitmap] 0)
                     (assoc-in [:query-params :pdfsettings] "/default")
+                    (assoc-in [:query-params :pdfaconformance] 2)
                     (merge (peridot.multipart/build {:file file})))
         response (app request)
         body (ring.util.request/body-string response)]