diff --git a/backend/zint.h b/backend/zint.h
index 5fbde5ca..75205ac2 100644
--- a/backend/zint.h
+++ b/backend/zint.h
@@ -283,6 +283,7 @@ extern "C" {
 #define GS1NOCHECK_MODE         0x0020  /* Do not check validity of GS1 data (except that printable ASCII only) */
 #define HEIGHTPERROW_MODE       0x0040  /* Interpret `height` as per-row rather than as overall height */
 #define FAST_MODE               0x0080  /* Use faster if less optimal encodation for symbologies that support it */
+                                        /* Note: only DATAMATRIX currently */
 
 /* Data Matrix specific options (`symbol->option_3`) */
 #define DM_SQUARE               100     /* Only consider square versions on automatic symbol size selection */
diff --git a/docs/manual.txt b/docs/manual.txt
index 10d52343..d6e68538 100644
--- a/docs/manual.txt
+++ b/docs/manual.txt
@@ -1514,6 +1514,8 @@ GS1NOCHECK_MODE   |  Do not check GS1 data for validity, i.e. suppress checks
                   |     checked for.
 HEIGHTPERROW_MODE |  Interpret the height variable as per-row rather than as
                   |     overall height.
+FAST_MODE         |  Use faster if less optimal encodation for symbologies that
+                  |     support it (currently DATAMATRIX only).
 --------------------------------------------------------------------------------
 
 The default mode is DATA_MODE.
@@ -2500,8 +2502,8 @@ DMRE symbol sizes may be activated in automatic size mode using the option
 GS1 data may be encoded using FNC1 (preferred) or GS as separator. Use the
 option --gssep to change to GS or use the API output_options |= GS1_GS_SEPARATOR
 
-For a near-optimal but slower encoding, the --compressenc option (API
-option_3 |= DM_COMPRESSION) may be used.
+For a faster but less optimal encoding, the --fast option (API input_mode |=
+FAST_MODE) may be used.
 
 Data Matrix supports Structured Append of up to 16 symbols and a numeric ID
 (file identifications), which can be set by using the --structapp option (see
@@ -3135,9 +3137,9 @@ Value | EC Level | Amount of symbol holding error correction data
 -----------------------------------------------------------------
 
 Zint does not currently implement data compression by default, but this can
-be initiated using the `--compressenc` option or through the API by setting
+be initiated through the API by setting
 
-symbol->option_3 |= ULTRA_COMPRESSION;
+symbol->option_3 = ULTRA_COMPRESSION;
 
 WARNING: Ultracode data compression is experimental and should not be used
 in a production environment.