diff --git a/ax_init_standard_project.m4 b/ax_init_standard_project.m4
index 0baa9ad..dfbd40c 100644
--- a/ax_init_standard_project.m4
+++ b/ax_init_standard_project.m4
@@ -365,7 +365,7 @@ AC_DEFUN([AX_USE_CXX], [
   CXXFLAGS="${CXXFLAGS//-g -O2/}"
   CFLAGS="${CFLAGS//-g -O2/}"
 
-# pass compile flags to make distcheck
+  # pass compile flags to make distcheck
   AM_DISTCHECK_CONFIGURE_FLAGS="CXXFLAGS='${CXXFLAGS}' CPPFLAGS='${CPPFLAGS}' CFLAGS='${CFLAGS}' LDFLAGS='${LDFLAGS}'"
   AC_SUBST(AM_DISTCHECK_CONFIGURE_FLAGS)
 
@@ -391,6 +391,20 @@ maintainer-clean-cxx-targets:
 EOF
 ])
 
+# require specific C++ version
+AC_DEFUN([AX_USE_CXX_11], [
+  AX_USE_CXX
+  AX_CXX_COMPILE_STDCXX([11], [noext], [mandatory])
+])
+AC_DEFUN([AX_USE_CXX_14], [
+  AX_USE_CXX
+  AX_CXX_COMPILE_STDCXX([14], [noext], [mandatory])
+])
+AC_DEFUN([AX_USE_CXX_17], [
+  AX_USE_CXX
+  AX_CXX_COMPILE_STDCXX([17], [noext], [mandatory])
+])
+
 # use this in configure.ac to support old school C
 AC_DEFUN([AX_USE_C], [
   AC_LANG(C)
@@ -637,7 +651,6 @@ AC_DEFUN([AX_USE_DOXYGEN], [
   AC_CHECK_PROG(have_doxygen, doxygen, yes, no)
   AC_CHECK_PROG(have_dot, dot, yes, no)
   AC_CHECK_PROG(have_mscgen, mscgen, yes, no)
-  AM_CONDITIONAL(NEED_PLANTUML, test "$have_doxygen" = "yes" -a "1.8.11" != $((echo "1.8.11"; doxygen -v 2>/dev/null) | sort -V | head -1))
   PDF_DOC=${PACKAGE_NAME}-${PACKAGE_VERSION}.pdf
   AC_SUBST(PDF_DOC)
   if test "$have_doxygen" = "no"; then
@@ -662,28 +675,12 @@ AC_DEFUN([AX_USE_DOXYGEN], [
   AX_ADD_MAKEFILE_TARGET_DEP([.PHONY], [pdf gen-uml-images], [doc/makefile.in])
   test -f doc/makefile.in && cat >> doc/makefile.in <<EOF
 #### Begin: Appended by $0
-doc: doxyfile @NEED_PLANTUML_TRUE@ gen-uml-images
-	@NEED_PLANTUML_TRUE@ doxyadd() { grep -q "\$\$[1] += \$\$[2]" doxyfile || sed -i '/^'"\$\$[1]"' *=/a'"\$\$[1]"' += '"\$\$[2]" doxyfile; }; \\
-	@NEED_PLANTUML_TRUE@ doxyadd ALIASES '"startuml{1}=@image html \\\\1\\\\n@image latex \\\\1\\\\n\\\\if DontIgnorePlantUMLCode"'; \\
-	@NEED_PLANTUML_TRUE@ doxyadd ALIASES '"enduml=\\\\endif"'; \\
-	@NEED_PLANTUML_TRUE@ doxyadd IMAGE_PATH '"gen-uml-images"';
+doc: doxyfile
 	doxygen doxyfile
 @PEDANTIC_TRUE@	test \! -s doxygen.errors
 
-@NEED_PLANTUML_TRUE@EXTRA_DIST = ${EXTRA_DIST} plantuml.jar
-@NEED_PLANTUML_TRUE@
-@NEED_PLANTUML_TRUE@gen-uml-images:
-@NEED_PLANTUML_TRUE@	test -d gen-uml-images || mkdir gen-uml-images
-@NEED_PLANTUML_TRUE@	eval \$\$(sed -n 's, *INPUT *\\(+\\?\\)= *\\(.*\\),INPUT\\1=" \\2",gp' doxyfile); \\
-@NEED_PLANTUML_TRUE@	eval \$\$(sed -n 's, *FILE_PATTERNS *\\(+\\?\\)= *\\(.*\\),FILE_PATTERNS\\1=" \\2",gp' doxyfile); \\
-@NEED_PLANTUML_TRUE@	SOURCES="**.("\$\$(echo \$\${FILE_PATTERNS} | sed 's,*.,,g;s, ,|,g')")"; \\
-@NEED_PLANTUML_TRUE@	for src in \$\$INPUT; do \\
-@NEED_PLANTUML_TRUE@	  java  -Djava.awt.headless=true -jar \${top_srcdir}/doc/plantuml.jar -v -o \$\$(pwd)/gen-uml-images "\$\$src/\$\$SOURCES"; \\
-@NEED_PLANTUML_TRUE@	done
-
 clean-documentation:
 	-rm doxygen.errors @PDF_DOC@
-	@NEED_PLANTUML_TRUE@ -rm -rf gen-uml-images
 distclean-documentation:
 	-rm -r html
 	-rm  @PACKAGE_NAME@.doxytag
diff --git a/build-in-docker.sh b/build-in-docker.sh
index 583cf9f..7b425be 100755
--- a/build-in-docker.sh
+++ b/build-in-docker.sh
@@ -7,7 +7,7 @@ if test "${arch}" = "amd64"; then
     myarch="amd64|i386"
 fi
 mode=
-img="mwaeckerlin/ubuntu:latest"
+img=
 repos=()
 keys=()
 dns=()
@@ -81,24 +81,27 @@ while test $# -gt 0; do
             echo
             exit 0
             ;;
-        (-m|--mode) shift;
+        (-m|--mode)
+            shift;
             mode="$1"
-            case "$mode" in
-                (deb|apt) img="mwaeckerlin/ubuntu:latest";;
-                (rpm|zypper) img="opensuse:latest";;
-                (yum) img="centos:latest";;
-                (dnf) img="fedora:latest";;
-                (win)
-                    img="mwaeckerlin/ubuntu:latest"; host="${host:---host=i686-w64-mingw32}"
-                    targets="all install"
-                    flags+=("--prefix=/workdir/usr")
-                    packages+=("mingw-w64")
-                    ;;
-                (*)
-                    echo "**** ERROR: unknown mode '$1', try --help" 1>&2
-                    exit 1
-                    ;;
-            esac
+            if test -z "$img"; then
+                case "$mode" in
+                    (deb|apt) img="mwaeckerlin/debbuildenv";;
+                    (rpm|zypper) img="opensuse:latest";;
+                    (yum) img="centos:latest";;
+                    (dnf) img="fedora:latest";;
+                    (win)
+                        img="mwaeckerlin/debbuildenv"; host="${host:---host=i686-w64-mingw32}"
+                        targets="all install"
+                        flags+=("--prefix=/workdir/usr")
+                        packages+=("mingw-w64")
+                        ;;
+                    (*)
+                        echo "**** ERROR: unknown mode '$1', try --help" 1>&2
+                        exit 1
+                        ;;
+                esac
+            fi
             ;;
         (-i|--image) shift;
             img="$1"
@@ -243,6 +246,9 @@ function ifthenelse() {
 
 set -x
 
+if test -z "$img"; then
+    img="mwaeckerlin/debbuildenv"
+fi
 docker pull $img
 DOCKER_ID=$(docker create ${dns[@]} ${dirs[@]} ${envs[@]} -w /workdir $img sleep infinity)
 trap 'traperror '"${DOCKER_ID}"' "$? ${PIPESTATUS[@]}" $LINENO $BASH_LINENO "$BASH_COMMAND" "${FUNCNAME[@]}" "${FUNCTION}"' SIGINT INT TERM EXIT
@@ -262,8 +268,8 @@ if test -z "$mode"; then
         (*deb*) mode=deb;;
         (*rpm*) mode=rpm;;
         (*) case "$img" in
-                (*ubuntu*|*debian*|*mint*) mode=deb;;
-                (*fedora*|*centos*|*mageia*) mode=rpm;;
+                (*deb*|*ubuntu*|*debian*|*mint*) mode=deb;;
+                (*rpm*|*fedora*|*centos*|*mageia*) mode=rpm;;
                 (*mingw*|*win*) mode=win;;
                 (*) mode=deb;;
             esac;;
diff --git a/configure.ac b/configure.ac
index 7fb67e0..f630597 100644
--- a/configure.ac
+++ b/configure.ac
@@ -10,7 +10,7 @@ AM_INIT_AUTOMAKE([1.9 tar-pax])
 AX_INIT_STANDARD_PROJECT
 
 # languages
-AX_USE_CXX
+AX_USE_CXX_11
 AX_USE_LIBTOOL
 AX_USE_DOXYGEN
 AX_USE_DEBIAN_PACKAGING
diff --git a/doc/plantuml.jar b/doc/plantuml.jar
index 9502c23..2fcafa0 100644
Binary files a/doc/plantuml.jar and b/doc/plantuml.jar differ
diff --git a/src/openssl.hxx b/src/openssl.hxx
index 9a45136..d1aba61 100644
--- a/src/openssl.hxx
+++ b/src/openssl.hxx
@@ -26,6 +26,12 @@
 #include <openssl/err.h>
 #include <vector>
 
+#if OPENSSL_VERSION_NUMBER < 0x10100000L
+inline const unsigned char* ASN1_STRING_get0_data(ASN1_STRING *x) {
+  return ASN1_STRING_data(x);
+}
+#endif
+
 #include <openssl/x509v3.h> // BASIC_CONSTRAINTS
 #include <openssl/bn.h>
 #include <cryptaux.hxx>