diff --git a/doc/user_guide/en/decoder_notes.adoc b/doc/user_guide/en/decoder_notes.adoc
index fafbdcd4e..7c083649f 100644
--- a/doc/user_guide/en/decoder_notes.adoc
+++ b/doc/user_guide/en/decoder_notes.adoc
@@ -2,12 +2,12 @@
 
 === AP Decoding
 
-The _WSJT-X_ decoders for FT4, FT8, JT65, QRA64, include 
+The _WSJT-X_ decoders for FST4, FT4, FT8, JT65, and QRA64 include 
 procedures that use naturally accumulating information during a
 minimal QSO.  This _a priori_ (AP) information increases sensitivity
 of the decoder by up to 4 dB, at the cost of a slightly higher rate of
 false decodes.  AP is optional in FT8, JT65, and QRA64, but is always
-enabled for FT4.
+enabled for FT4 and FST4 when decode depth is Normal or Deep.
 
 For example: when you decide to answer a CQ, you already know your own
 callsign and that of your potential QSO partner.  The software
@@ -27,7 +27,7 @@ example, `a2` indicates that the successful decode used MyCall as
 hypothetically known information.
 
 [[FT8_AP_INFO_TABLE]]
-.FT4 and FT8 AP information types
+.FST4, FT4, and FT8 AP information types
 [width="35%",cols="h10,<m20",frame=topbot,options="header"]
 |===============================================
 |aP | Message components
@@ -47,7 +47,9 @@ forwarded to {pskreporter}.
 
 Table 2 lists the six possible QSO states that are tracked by the
 _WSJT-X_ auto-sequencer, along with the type of AP decoding that would
-be attempted in each state.
+be attempted in each state in FT4 or FT8. The FST4 table (not shown) 
+is the same except that it omits the decoding attempts for AP types 
+4 and 5 to save time.
 
 [[FT8_AP_DECODING_TYPES_TABLE]]
 .FT4 and FT8 AP decoding types for each QSO state
@@ -109,13 +111,15 @@ summarized in the following Table:
 [width="50%",cols="h,3*^",frame=topbot,options="header"]
 |===========================================
 |Mode    |Mode character|Sync character|End of line information
+|FST4    | `            |      | ? &#160; aP
 |FT4     | ~            |      | ? &#160; aP
 |FT8     | ~            |      | ? &#160; aP
 |JT4     | $            | *, # | f, fN, dCN
 |JT9     | @            |      |
 |JT65    | #            |      |
 |JT65 VHF| #            | *, # | f, fN, dCN
-|QRA64   | :            | *    | R
+|QRA64   | :            | *    | R:w
+
 |ISCAT   |              | *    | M  N  C  T
 |MSK144  | &            |      |
 |===========================================