diff --git a/Lib/fontTools/misc/etree.py b/Lib/fontTools/misc/etree.py
index dc7bb093c..08e43f0a5 100644
--- a/Lib/fontTools/misc/etree.py
+++ b/Lib/fontTools/misc/etree.py
@@ -14,10 +14,8 @@ iterwalk.
 from __future__ import absolute_import, unicode_literals
 from fontTools.misc.py23 import basestring, unicode, tounicode, open
 
-# we use a custom XML declaration for backward compatibility with older
-# ufoLib versions which would write it using double quotes.
-# https://github.com/unified-font-object/ufoLib/issues/158
-XML_DECLARATION = """<?xml version="1.0" encoding="%s"?>"""
+
+XML_DECLARATION = """<?xml version='1.0' encoding='%s'?>"""
 
 __all__ = [
     # public symbols
diff --git a/Lib/fontTools/misc/plistlib.py b/Lib/fontTools/misc/plistlib.py
index a4dc307ad..fe6959368 100644
--- a/Lib/fontTools/misc/plistlib.py
+++ b/Lib/fontTools/misc/plistlib.py
@@ -41,10 +41,7 @@ if PY3:
 else:
     USE_BUILTIN_TYPES = False
 
-# we use a custom XML declaration for backward compatibility with older
-# ufoLib versions which would write it using double quotes.
-# https://github.com/unified-font-object/ufoLib/issues/158
-XML_DECLARATION = b"""<?xml version="1.0" encoding="UTF-8"?>"""
+XML_DECLARATION = b"""<?xml version='1.0' encoding='UTF-8'?>"""
 
 PLIST_DOCTYPE = (
     b'<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" '
diff --git a/Lib/fontTools/ufoLib/glifLib.py b/Lib/fontTools/ufoLib/glifLib.py
index db977a098..eae300b20 100755
--- a/Lib/fontTools/ufoLib/glifLib.py
+++ b/Lib/fontTools/ufoLib/glifLib.py
@@ -575,9 +575,6 @@ def readGlyphFromString(aString, glyphObject=None, pointPen=None, formatVersions
 	_readGlyphFromTree(tree, glyphObject, pointPen, formatVersions=formatVersions, validate=validate)
 
 
-_XML_DECLARATION = plistlib.XML_DECLARATION + b"\n"
-
-
 def _writeGlyphToBytes(
 		glyphName, glyphObject=None, drawPointsFunc=None, writer=None,
 		formatVersion=2, validate=True):
@@ -621,8 +618,8 @@ def _writeGlyphToBytes(
 	if getattr(glyphObject, "lib", None):
 		_writeLib(glyphObject, root, validate)
 	# return the text
-	data = _XML_DECLARATION + etree.tostring(
-		root, encoding="utf-8", xml_declaration=False, pretty_print=True
+	data = etree.tostring(
+		root, encoding="UTF-8", xml_declaration=True, pretty_print=True
 	)
 	return data
 
diff --git a/Tests/ufoLib/glifLib_test.py b/Tests/ufoLib/glifLib_test.py
index 43b350662..3bcd07c1a 100644
--- a/Tests/ufoLib/glifLib_test.py
+++ b/Tests/ufoLib/glifLib_test.py
@@ -7,8 +7,8 @@ from io import open
 from .testSupport import getDemoFontGlyphSetPath
 from fontTools.ufoLib.glifLib import (
 	GlyphSet, glyphNameToFileName, readGlyphFromString, writeGlyphToString,
-	_XML_DECLARATION,
 )
+from fontTools.misc.etree import XML_DECLARATION
 
 GLYPHSETDIR = getDemoFontGlyphSetPath()
 
@@ -161,4 +161,4 @@ class ReadWriteFuncTest(unittest.TestCase):
 
 	def testXmlDeclaration(self):
 		s = writeGlyphToString("a", _Glyph())
-		self.assertTrue(s.startswith(_XML_DECLARATION.decode("utf-8")))
+		self.assertTrue(s.startswith(XML_DECLARATION % "UTF-8"))