diff --git a/doc/updating_waf.txt b/doc/updating_waf.txt
index 69c1225d63..0c192d4489 100644
--- a/doc/updating_waf.txt
+++ b/doc/updating_waf.txt
@@ -1,15 +1,20 @@
-Download waf (https://waf.io/)
-
-autowaf.py is present in the tools directory of the Ardour source code.
-a patch for C++11/clang can be found in tools/waflib.patch (needed for waf 1.8.19)
-
-Current waf is build as follows;
+# Download waf (https://waf.io/)
+#
+# autowaf.py and misc.py are present in the tools directory of the Ardour source code.
+# - waf-str.patch is needed for py2/py3 compatible install_dir:
+#  * in py2 paths are byte-arrays and would need to be converted using .encode("utf-8")
+#    (otherwise waf expands them /t/o/p/a/t/h/s/l/i/k/e/t/h/i/s)
+#  * however py3 cannot handled encoded arrays:
+#    (TypeError: cannot use a string pattern on a bytes-like object)
+#
+# Current waf is build as follows:
 
 ARDOURSRC=`pwd`
 cd /tmp
-curl https://waf.io/waf-1.6.11.tar.bz2 | tar xj
-cd waf-1.6.11
+curl https://waf.io/waf-2.0.19.tar.bz2 | tar xj
+cd waf-2.0.19
 
-patch -p1 < $ARDOURSRC/tools/waflib.patch
-./waf-light -v --make-waf --tools=misc,doxygen,$ARDOURSRC/tools/autowaf.py --prelude=''
+patch -p1 < $ARDOURSRC/tools/waf-str.patch
+
+./waf-light -v --make-waf --tools=misc,doxygen,$ARDOURSRC/tools/autowaf.py,$ARDOURSRC/tools/misc.py --prelude=''
 cp ./waf $ARDOURSRC/waf
diff --git a/tools/autowaf.py b/tools/autowaf.py
index f82b80a83f..375dc5909a 100644
--- a/tools/autowaf.py
+++ b/tools/autowaf.py
@@ -140,14 +140,13 @@ def check_pkg(conf, name, **args):
         found = None
         pkg_var_name = 'PKG_' + name.replace('-', '_')
         pkg_name = name
-        if conf.env.PARDEBUG:
-            args['mandatory'] = False  # Smash mandatory arg
-            found = conf.check_cfg(package=pkg_name + 'D', args="--cflags --libs", **args)
-            if found:
-                pkg_name += 'D'
         if mandatory:
             args['mandatory'] = True  # Unsmash mandatory arg
-        if not found:
+        if 'atleast_version' in args:
+            if not 'msg' in args:
+                args['msg'] = 'Checking for %r >= %s' %(pkg_name, args['atleast_version'])
+            found = conf.check_cfg(package=pkg_name, args=[pkg_name + " >= " + args['atleast_version'], '--cflags', '--libs'], **args)
+        else:
             found = conf.check_cfg(package=pkg_name, args="--cflags --libs", **args)
         if found:
             conf.env[pkg_var_name] = pkg_name
diff --git a/tools/misc.py b/tools/misc.py
index e8620fb14a..b82cdb63ba 100644
--- a/tools/misc.py
+++ b/tools/misc.py
@@ -80,67 +80,6 @@ def apply_copy(self):
 			tsk.debug()
 			raise Errors.WafError('task without an environment')
 
-def subst_func(tsk):
-	"Substitutes variables in a .in file"
-
-	m4_re = re.compile('@(\w+)@', re.M)
-
-	code = tsk.inputs[0].read() #Utils.readf(infile)
-
-	# replace all % by %% to prevent errors by % signs in the input file while string formatting
-	code = code.replace('%', '%%')
-
-	s = m4_re.sub(r'%(\1)s', code)
-
-	env = tsk.env
-	di = getattr(tsk, 'dict', {}) or getattr(tsk.generator, 'dict', {})
-	if not di:
-		names = m4_re.findall(code)
-		for i in names:
-			di[i] = env.get_flat(i) or env.get_flat(i.upper())
-
-	tsk.outputs[0].write(s % di)
-
-@feature('subst')
-@before_method('process_source')
-def apply_subst(self):
-	Utils.def_attrs(self, fun=subst_func)
-	lst = self.to_list(self.source)
-	self.meths.remove('process_source')
-
-	self.dict = getattr(self, 'dict', {})
-
-	for filename in lst:
-		node = self.path.find_resource(filename)
-		if not node: raise Errors.WafError('cannot find input file %s for processing' % filename)
-
-		if self.target:
-			newnode = self.path.find_or_declare(self.target)
-		else:
-			newnode = node.change_ext('')
-
-		try:
-			self.dict = self.dict.get_merged_dict()
-		except AttributeError:
-			pass
-
-		if self.dict and not self.env['DICT_HASH']:
-			self.env = self.env.derive()
-			keys = list(self.dict.keys())
-			keys.sort()
-			lst = [self.dict[x] for x in keys]
-			self.env['DICT_HASH'] = str(Utils.h_list(lst))
-
-		tsk = self.create_task('copy', node, newnode)
-		tsk.fun = self.fun
-		tsk.dict = self.dict
-		tsk.dep_vars = ['DICT_HASH']
-		tsk.chmod = getattr(self, 'chmod', Utils.O644)
-
-		if not tsk.env:
-			tsk.debug()
-			raise Errors.WafError('task without an environment')
-
 ####################
 ## command-output ####
 ####################
diff --git a/tools/waf-str.patch b/tools/waf-str.patch
new file mode 100644
index 0000000000..8d37f68d32
--- /dev/null
+++ b/tools/waf-str.patch
@@ -0,0 +1,11 @@
+--- a/waflib/Build.py	2020-01-21 15:01:13.864899388 +0100
++++ b/waflib/Build.py	2020-01-21 15:01:59.573030630 +0100
+@@ -953,7 +953,7 @@
+ 	tsk.link = kw.get('link', '') or kw.get('install_from', '')
+ 	tsk.relative_trick = kw.get('relative_trick', False)
+ 	tsk.type = kw['type']
+-	tsk.install_to = tsk.dest = kw['install_to']
++	tsk.install_to = tsk.dest = str(kw['install_to'])
+ 	tsk.install_from = kw['install_from']
+ 	tsk.relative_base = kw.get('cwd') or kw.get('relative_base', self.path)
+ 	tsk.install_user = kw.get('install_user')
diff --git a/waf b/waf
index 7363144d4b..da7d3440ed 100755
Binary files a/waf and b/waf differ