diff --git a/ext/mbstring/libmbfl/filters/mbfilter_iso8859_10.c b/ext/mbstring/libmbfl/filters/mbfilter_iso8859_10.c
index e82c52f4b6a..62179fa001b 100644
--- a/ext/mbstring/libmbfl/filters/mbfilter_iso8859_10.c
+++ b/ext/mbstring/libmbfl/filters/mbfilter_iso8859_10.c
@@ -83,11 +83,6 @@ int mbfl_filt_conv_8859_10_wchar(int c, mbfl_convert_filter *filter)
 		s = c;
 	} else if (c >= 0xa0 && c < 0x100) {
 		s = iso8859_10_ucs_table[c - 0xa0];
-		if (s <= 0) {
-			s = c;
-			s &= MBFL_WCSPLANE_MASK;
-			s |= MBFL_WCSPLANE_8859_10;
-		}
 	} else {
 		s = c;
 		s &= MBFL_WCSGROUP_MASK;
@@ -118,9 +113,6 @@ int mbfl_filt_conv_wchar_8859_10(int c, mbfl_convert_filter *filter)
 			}
 			n--;
 		}
-		if (s <= 0 && (c & ~MBFL_WCSPLANE_MASK) == MBFL_WCSPLANE_8859_10) {
-			s = c & MBFL_WCSPLANE_MASK;
-		}
 	}
 
 	if (s >= 0) {
diff --git a/ext/mbstring/libmbfl/filters/mbfilter_iso8859_13.c b/ext/mbstring/libmbfl/filters/mbfilter_iso8859_13.c
index ec5d5348a3f..88651baf652 100644
--- a/ext/mbstring/libmbfl/filters/mbfilter_iso8859_13.c
+++ b/ext/mbstring/libmbfl/filters/mbfilter_iso8859_13.c
@@ -83,11 +83,6 @@ int mbfl_filt_conv_8859_13_wchar(int c, mbfl_convert_filter *filter)
 		s = c;
 	} else if (c >= 0xa0 && c < 0x100) {
 		s = iso8859_13_ucs_table[c - 0xa0];
-		if (s <= 0) {
-			s = c;
-			s &= MBFL_WCSPLANE_MASK;
-			s |= MBFL_WCSPLANE_8859_13;
-		}
 	} else {
 		s = c;
 		s &= MBFL_WCSGROUP_MASK;
@@ -118,9 +113,6 @@ int mbfl_filt_conv_wchar_8859_13(int c, mbfl_convert_filter *filter)
 			}
 			n--;
 		}
-		if (s <= 0 && (c & ~MBFL_WCSPLANE_MASK) == MBFL_WCSPLANE_8859_13) {
-			s = c & MBFL_WCSPLANE_MASK;
-		}
 	}
 
 	if (s >= 0) {
diff --git a/ext/mbstring/libmbfl/filters/mbfilter_iso8859_14.c b/ext/mbstring/libmbfl/filters/mbfilter_iso8859_14.c
index ac5b9a40d91..515637ef047 100644
--- a/ext/mbstring/libmbfl/filters/mbfilter_iso8859_14.c
+++ b/ext/mbstring/libmbfl/filters/mbfilter_iso8859_14.c
@@ -83,11 +83,6 @@ int mbfl_filt_conv_8859_14_wchar(int c, mbfl_convert_filter *filter)
 		s = c;
 	} else if (c >= 0xa0 && c < 0x100) {
 		s = iso8859_14_ucs_table[c - 0xa0];
-		if (s <= 0) {
-			s = c;
-			s &= MBFL_WCSPLANE_MASK;
-			s |= MBFL_WCSPLANE_8859_14;
-		}
 	} else {
 		s = c;
 		s &= MBFL_WCSGROUP_MASK;
@@ -118,9 +113,6 @@ int mbfl_filt_conv_wchar_8859_14(int c, mbfl_convert_filter *filter)
 			}
 			n--;
 		}
-		if (s <= 0 && (c & ~MBFL_WCSPLANE_MASK) == MBFL_WCSPLANE_8859_14) {
-			s = c & MBFL_WCSPLANE_MASK;
-		}
 	}
 
 	if (s >= 0) {
diff --git a/ext/mbstring/libmbfl/filters/mbfilter_iso8859_15.c b/ext/mbstring/libmbfl/filters/mbfilter_iso8859_15.c
index 7d9e21e5c36..070d08dbe14 100644
--- a/ext/mbstring/libmbfl/filters/mbfilter_iso8859_15.c
+++ b/ext/mbstring/libmbfl/filters/mbfilter_iso8859_15.c
@@ -83,11 +83,6 @@ int mbfl_filt_conv_8859_15_wchar(int c, mbfl_convert_filter *filter)
 		s = c;
 	} else if (c >= 0xa0 && c < 0x100) {
 		s = iso8859_15_ucs_table[c - 0xa0];
-		if (s <= 0) {
-			s = c;
-			s &= MBFL_WCSPLANE_MASK;
-			s |= MBFL_WCSPLANE_8859_15;
-		}
 	} else {
 		s = c;
 		s &= MBFL_WCSGROUP_MASK;
@@ -118,9 +113,6 @@ int mbfl_filt_conv_wchar_8859_15(int c, mbfl_convert_filter *filter)
 			}
 			n--;
 		}
-		if (s <= 0 && (c & ~MBFL_WCSPLANE_MASK) == MBFL_WCSPLANE_8859_15) {
-			s = c & MBFL_WCSPLANE_MASK;
-		}
 	}
 
 	if (s >= 0) {
diff --git a/ext/mbstring/libmbfl/filters/mbfilter_iso8859_16.c b/ext/mbstring/libmbfl/filters/mbfilter_iso8859_16.c
index 5c8ae964be8..c1035020110 100644
--- a/ext/mbstring/libmbfl/filters/mbfilter_iso8859_16.c
+++ b/ext/mbstring/libmbfl/filters/mbfilter_iso8859_16.c
@@ -83,11 +83,6 @@ int mbfl_filt_conv_8859_16_wchar(int c, mbfl_convert_filter *filter)
 		s = c;
 	} else if (c >= 0xa0 && c < 0x100) {
 		s = iso8859_16_ucs_table[c - 0xa0];
-		if (s <= 0) {
-			s = c;
-			s &= MBFL_WCSPLANE_MASK;
-			s |= MBFL_WCSPLANE_8859_16;
-		}
 	} else {
 		s = c;
 		s &= MBFL_WCSGROUP_MASK;
@@ -118,9 +113,6 @@ int mbfl_filt_conv_wchar_8859_16(int c, mbfl_convert_filter *filter)
 			}
 			n--;
 		}
-		if (s <= 0 && (c & ~MBFL_WCSPLANE_MASK) == MBFL_WCSPLANE_8859_16) {
-			s = c & MBFL_WCSPLANE_MASK;
-		}
 	}
 
 	if (s >= 0) {
diff --git a/ext/mbstring/libmbfl/filters/mbfilter_iso8859_2.c b/ext/mbstring/libmbfl/filters/mbfilter_iso8859_2.c
index deacf0c0f4d..2aab9d2c168 100644
--- a/ext/mbstring/libmbfl/filters/mbfilter_iso8859_2.c
+++ b/ext/mbstring/libmbfl/filters/mbfilter_iso8859_2.c
@@ -84,11 +84,6 @@ int mbfl_filt_conv_8859_2_wchar(int c, mbfl_convert_filter *filter)
 		s = c;
 	} else if (c >= 0xa0 && c < 0x100) {
 		s = iso8859_2_ucs_table[c - 0xa0];
-		if (s <= 0) {
-			s = c;
-			s &= MBFL_WCSPLANE_MASK;
-			s |= MBFL_WCSPLANE_8859_2;
-		}
 	} else {
 		s = c;
 		s &= MBFL_WCSGROUP_MASK;
@@ -119,9 +114,6 @@ int mbfl_filt_conv_wchar_8859_2(int c, mbfl_convert_filter *filter)
 			}
 			n--;
 		}
-		if (s <= 0 && (c & ~MBFL_WCSPLANE_MASK) == MBFL_WCSPLANE_8859_2) {
-			s = c & MBFL_WCSPLANE_MASK;
-		}
 	}
 
 	if (s >= 0) {
diff --git a/ext/mbstring/libmbfl/filters/mbfilter_iso8859_4.c b/ext/mbstring/libmbfl/filters/mbfilter_iso8859_4.c
index 263036f27b4..a869230355e 100644
--- a/ext/mbstring/libmbfl/filters/mbfilter_iso8859_4.c
+++ b/ext/mbstring/libmbfl/filters/mbfilter_iso8859_4.c
@@ -83,11 +83,6 @@ int mbfl_filt_conv_8859_4_wchar(int c, mbfl_convert_filter *filter)
 		s = c;
 	} else if (c >= 0xa0 && c < 0x100) {
 		s = iso8859_4_ucs_table[c - 0xa0];
-		if (s <= 0) {
-			s = c;
-			s &= MBFL_WCSPLANE_MASK;
-			s |= MBFL_WCSPLANE_8859_4;
-		}
 	} else {
 		s = c;
 		s &= MBFL_WCSGROUP_MASK;
@@ -118,9 +113,6 @@ int mbfl_filt_conv_wchar_8859_4(int c, mbfl_convert_filter *filter)
 			}
 			n--;
 		}
-		if (s <= 0 && (c & ~MBFL_WCSPLANE_MASK) == MBFL_WCSPLANE_8859_4) {
-			s = c & MBFL_WCSPLANE_MASK;
-		}
 	}
 
 	if (s >= 0) {
diff --git a/ext/mbstring/libmbfl/filters/mbfilter_iso8859_5.c b/ext/mbstring/libmbfl/filters/mbfilter_iso8859_5.c
index b9a6132029f..33698e563d5 100644
--- a/ext/mbstring/libmbfl/filters/mbfilter_iso8859_5.c
+++ b/ext/mbstring/libmbfl/filters/mbfilter_iso8859_5.c
@@ -84,11 +84,6 @@ int mbfl_filt_conv_8859_5_wchar(int c, mbfl_convert_filter *filter)
 		s = c;
 	} else if (c >= 0xa0 && c < 0x100) {
 		s = iso8859_5_ucs_table[c - 0xa0];
-		if (s <= 0) {
-			s = c;
-			s &= MBFL_WCSPLANE_MASK;
-			s |= MBFL_WCSPLANE_8859_5;
-		}
 	} else {
 		s = c;
 		s &= MBFL_WCSGROUP_MASK;
@@ -119,9 +114,6 @@ int mbfl_filt_conv_wchar_8859_5(int c, mbfl_convert_filter *filter)
 			}
 			n--;
 		}
-		if (s <= 0 && (c & ~MBFL_WCSPLANE_MASK) == MBFL_WCSPLANE_8859_5) {
-			s = c & MBFL_WCSPLANE_MASK;
-		}
 	}
 
 	if (s >= 0) {
diff --git a/ext/mbstring/libmbfl/filters/mbfilter_iso8859_9.c b/ext/mbstring/libmbfl/filters/mbfilter_iso8859_9.c
index a2b87d1174b..f4241982cf6 100644
--- a/ext/mbstring/libmbfl/filters/mbfilter_iso8859_9.c
+++ b/ext/mbstring/libmbfl/filters/mbfilter_iso8859_9.c
@@ -83,11 +83,6 @@ int mbfl_filt_conv_8859_9_wchar(int c, mbfl_convert_filter *filter)
 		s = c;
 	} else if (c >= 0xa0 && c < 0x100) {
 		s = iso8859_9_ucs_table[c - 0xa0];
-		if (s <= 0) {
-			s = c;
-			s &= MBFL_WCSPLANE_MASK;
-			s |= MBFL_WCSPLANE_8859_9;
-		}
 	} else {
 		s = c;
 		s &= MBFL_WCSGROUP_MASK;
@@ -118,9 +113,6 @@ int mbfl_filt_conv_wchar_8859_9(int c, mbfl_convert_filter *filter)
 			}
 			n--;
 		}
-		if (s <= 0 && (c & ~MBFL_WCSPLANE_MASK) == MBFL_WCSPLANE_8859_9) {
-			s = c & MBFL_WCSPLANE_MASK;
-		}
 	}
 
 	if (s >= 0) {
diff --git a/ext/mbstring/libmbfl/mbfl/mbfl_consts.h b/ext/mbstring/libmbfl/mbfl/mbfl_consts.h
index 3570aa891d2..1ddaa381a5a 100644
--- a/ext/mbstring/libmbfl/mbfl/mbfl_consts.h
+++ b/ext/mbstring/libmbfl/mbfl/mbfl_consts.h
@@ -51,26 +51,16 @@
 #define MBFL_WCSPLANE_JIS0208		0x70e10000		/* JIS HEX : 2121h - 7E7Eh */
 #define MBFL_WCSPLANE_JIS0212		0x70e20000		/* JIS HEX : 2121h - 7E7Eh */
 #define MBFL_WCSPLANE_WINCP932		0x70e30000		/* JIS HEX : 2121h - 9898h */
-#define MBFL_WCSPLANE_8859_1		0x70e40000		/*  00h - FFh */
-#define MBFL_WCSPLANE_8859_2		0x70e50000		/*  00h - FFh */
 #define MBFL_WCSPLANE_8859_3		0x70e60000		/*  00h - FFh */
-#define MBFL_WCSPLANE_8859_4		0x70e70000		/*  00h - FFh */
-#define MBFL_WCSPLANE_8859_5		0x70e80000		/*  00h - FFh */
 #define MBFL_WCSPLANE_8859_6		0x70e90000		/*  00h - FFh */
 #define MBFL_WCSPLANE_8859_7		0x70ea0000		/*  00h - FFh */
 #define MBFL_WCSPLANE_8859_8		0x70eb0000		/*  00h - FFh */
-#define MBFL_WCSPLANE_8859_9		0x70ec0000		/*  00h - FFh */
-#define MBFL_WCSPLANE_8859_10		0x70ed0000		/*  00h - FFh */
-#define MBFL_WCSPLANE_8859_13		0x70ee0000		/*  00h - FFh */
-#define MBFL_WCSPLANE_8859_14		0x70ef0000		/*  00h - FFh */
-#define MBFL_WCSPLANE_8859_15		0x70f00000		/*  00h - FFh */
 #define MBFL_WCSPLANE_KSC5601		0x70f10000		/*  2121h - 7E7Eh */
 #define MBFL_WCSPLANE_GB2312		0x70f20000		/*  2121h - 7E7Eh */
 #define MBFL_WCSPLANE_WINCP936		0x70f30000		/*  2121h - 9898h */
 #define MBFL_WCSPLANE_BIG5		0x70f40000		/*  2121h - 9898h */
 #define MBFL_WCSPLANE_CNS11643		0x70f50000		/*  2121h - 9898h */
 #define MBFL_WCSPLANE_UHC		0x70f60000		/*  8141h - fefeh */
-#define MBFL_WCSPLANE_8859_16		0x70fa0000		/*  00h - FFh */
 #define MBFL_WCSPLANE_ARMSCII8 		0x70fb0000
 #define MBFL_WCSPLANE_KOI8U 		0x70fc0000
 #define MBFL_WCSPLANE_GB18030		0x70ff0000		/* a1a1h-e3329a35h  */
diff --git a/ext/mbstring/libmbfl/mbfl/mbfl_convert.c b/ext/mbstring/libmbfl/mbfl/mbfl_convert.c
index af6a3bba93b..8f2da2329f2 100644
--- a/ext/mbstring/libmbfl/mbfl/mbfl_convert.c
+++ b/ext/mbstring/libmbfl/mbfl/mbfl_convert.c
@@ -287,9 +287,6 @@ int mbfl_filt_conv_illegal_output(int c, mbfl_convert_filter *filter)
 					case MBFL_WCSPLANE_GB18030:
 						ret = mbfl_convert_filter_strcat(filter, (const unsigned char *)"GB+");
 						break;
-					case MBFL_WCSPLANE_8859_1:
-						ret = mbfl_convert_filter_strcat(filter, (const unsigned char *)"I8859_1+");
-						break;
 					default:
 						ret = mbfl_convert_filter_strcat(filter, (const unsigned char *)"?+");
 						break;