Update the Release Notes in preparation for a 2.4.0-rc4 release.

Release_Notes.txt

@@ -11,6 +11,38 @@
                                                          
 Copyright 2001 - 2021 by Joe Taylor, K1JT.
 
+	        Release: WSJT-X 2.4.0-rc3
+	               Mar 20, 2021
+	        -------------------------
+
+WSJT-X 2.4.0 Release Candidate 4 adds new Q65 mode functionality and
+decoder optimizations and repairs several defects and regressions
+discovered in the RC3 and v2.3.0 GA releases.
+
+ - Correct a problem with display of Q65 sync curves for submodes
+   Q65-120x and Q65-300x.
+
+ - Audio frequency and decoded message are now saved for up to 100
+   of the most recent Q65 decodes.  Subsequent double-click on
+   waterfall will search the list for that frequency +/- 10 Hz,
+   recover "DXCall" from the mosr recent decode there, and attempt
+   a q3-type decode at that frequency.
+
+ - Use new ADIF recommendations for Q65: mode=MSK, submode=Q65.
+
+ - If "Single decode" is unchecked, ;ook for Q65 decodes from
+   accumulated average even after obtaining a single-sequence
+   decode at selected Rx Freq.
+
+ - Display original UTC (derived from file name) on the waterfall,
+   for data read from .wav files.
+
+ - Corrected several bounds errors caused by unusual settings on
+   Wide Graph.
+
+ - Correct a problem with Split operation in FT4 mode.  Thanks to
+   JG1APX.
+
 
 	        Release: WSJT-X 2.4.0-rc3
 	               Mar 15, 2021