diff --git a/crates/pdf_io/pdf_io/dpx-cidtype2.c b/crates/pdf_io/pdf_io/dpx-cidtype2.c
index 5f1ec842b..76bb24fd0 100644
--- a/crates/pdf_io/pdf_io/dpx-cidtype2.c
+++ b/crates/pdf_io/pdf_io/dpx-cidtype2.c
@@ -147,7 +147,7 @@ validate_name (char *fontname, int len)
  */
 
 #define WIN_UCS_INDEX_MAX   1
-#define KNOWN_ENCODINGS_MAX 9
+#define KNOWN_ENCODINGS_MAX 10
 static struct
 {
     unsigned short  platform;
@@ -164,6 +164,7 @@ static struct
     {TT_MAC, TT_MAC_TRADITIONAL_CHINESE, {"B5pc",     NULL}},
     {TT_MAC, TT_MAC_SIMPLIFIED_CHINESE,  {"GBpc-EUC", NULL}},
     {TT_MAC, TT_MAC_KOREAN,   {"KSCpc-EUC", NULL}},
+    {0, 4,  {"UCSms-UCS4", "UCSms-UCS2", "UCS4", "UCS2", NULL}},
     {0, 0, {NULL}}
 };
 
diff --git a/crates/pdf_io/pdf_io/dpx-tt_cmap.c b/crates/pdf_io/pdf_io/dpx-tt_cmap.c
index e85599a3e..1a5330697 100644
--- a/crates/pdf_io/pdf_io/dpx-tt_cmap.c
+++ b/crates/pdf_io/pdf_io/dpx-tt_cmap.c
@@ -1047,6 +1047,7 @@ typedef struct {
 static cmap_plat_enc_rec cmap_plat_encs[] = {
     { 3, 10 },
     { 0, 3 },
+    { 0, 4 },
     { 0, 0 },
     { 3, 1 },
     { 0, 1 }