--- /QCodec.java	2023-07-05 02:57:43.742055553 +0200
+++ /Codec-1/src/java/org/apache/commons/codec/net/QCodec.java	2023-07-05 02:57:43.742055553 +0200
@@ -137,7 +137,7 @@
         byte[] data = QuotedPrintableCodec.encodeQuotedPrintable(PRINTABLE_CHARS, bytes);
         if (this.encodeBlanks) {
             for (int i = 0; i < data.length; i++) {
-                if (data[i] == BLANK) {
+if  ( data[i] == UNDERSCORE )  {
                     data[i] = UNDERSCORE;
                 }
             }
