Index: library/Zend/Mime.php
===================================================================
--- library/Zend/Mime.php	(revision 24554)
+++ library/Zend/Mime.php	(working copy)
@@ -130,7 +130,7 @@
         $str = self::_encodeQuotedPrintable($str);
 
         // Split encoded text into separate lines
-        while ($str) {
+        while(strlen($str) > 0) {
             $ptr = strlen($str);
             if ($ptr > $lineLength) {
                 $ptr = $lineLength;
Index: tests/Zend/MimeTest.php
===================================================================
--- tests/Zend/MimeTest.php	(revision 24554)
+++ tests/Zend/MimeTest.php	(working copy)
@@ -73,6 +73,17 @@
         $this->assertEquals(quoted_printable_decode($qp), $text);
     }
 
+    /**
+     * @group ZF-10074
+     */
+    public function testEncodeQuotedPrintableWhenTextHasZeroAtTheEnd()
+    {
+        $raw = str_repeat('x',72) . '0';
+        $quoted = Zend_Mime::encodeQuotedPrintable($raw, 72);
+        $expected = quoted_printable_decode($quoted);        
+        $this->assertEquals($expected, $raw);
+    }
+
     public function testBase64()
     {
         $content = str_repeat("\x88\xAA\xAF\xBF\x29\x88\xAA\xAF\xBF\x29\x88\xAA\xAF", 4);