diff --git a/include/mdbtools.h b/include/mdbtools.h
index 66f2cd2..89b8a24 100644
--- a/include/mdbtools.h
+++ b/include/mdbtools.h
@@ -58,7 +58,8 @@ enum {
 };
 enum {
 	MDB_VER_JET3 = 0,
-	MDB_VER_JET4 = 1
+	MDB_VER_JET4 = 1,
+	MDB_VER_JET5 = 2
 };
 enum {
 	MDB_FORM = 0,
@@ -165,6 +166,7 @@ enum {
 };
 #define MDB_SHEXP_DEFAULT (MDB_SHEXP_CST_NOTNULL | MDB_SHEXP_COMMENTS | MDB_SHEXP_INDEXES | MDB_SHEXP_RELATIONS)
 
+#define IS_JET5(mdb) (mdb->f->jet_version==MDB_VER_JET5)
 #define IS_JET4(mdb) (mdb->f->jet_version==MDB_VER_JET4)
 #define IS_JET3(mdb) (mdb->f->jet_version==MDB_VER_JET3)
 
diff --git a/src/libmdb/file.c b/src/libmdb/file.c
index e23ac8a..1816923 100644
--- a/src/libmdb/file.c
+++ b/src/libmdb/file.c
@@ -217,7 +217,9 @@ MdbHandle *mdb_open(const char *filename, MdbFileFlags flags)
 		return NULL; 
 	}
 	mdb->f->jet_version = mdb_get_int32(mdb->pg_buf, 0x14);
-	if (IS_JET4(mdb)) {
+	if (IS_JET5(mdb)) {
+		mdb->fmt = &MdbJet4Constants;
+	} else if (IS_JET4(mdb)) {
 		mdb->fmt = &MdbJet4Constants;
 	} else if (IS_JET3(mdb)) {
 		mdb->fmt = &MdbJet3Constants;
diff --git a/src/libmdb/iconv.c b/src/libmdb/iconv.c
index 1ae303a..cd2cd93 100644
--- a/src/libmdb/iconv.c
+++ b/src/libmdb/iconv.c
@@ -38,7 +38,7 @@ mdb_unicode2ascii(MdbHandle *mdb, char *src, size_t slen, char *dest, size_t dle
 		return 0;
 
 	/* Uncompress 'Unicode Compressed' string into tmp */
-	if (IS_JET4(mdb) && (slen>=2)
+	if (!IS_JET3(mdb) && (slen>=2)
 	 && ((src[0]&0xff)==0xff) && ((src[1]&0xff)==0xfe)) {
 		unsigned int compress=1;
 		src += 2;
@@ -72,8 +72,8 @@ mdb_unicode2ascii(MdbHandle *mdb, char *src, size_t slen, char *dest, size_t dle
 		iconv(mdb->iconv_in, &in_ptr, &len_in, &out_ptr, &len_out);
 		if ((!len_in) || (errno == E2BIG)) break;
 		/* Don't bail if impossible conversion is encountered */
-		in_ptr += (IS_JET4(mdb)) ? 2 : 1;
-		len_in -= (IS_JET4(mdb)) ? 2 : 1;
+		in_ptr += (IS_JET3(mdb)) ? 1 : 2;
+		len_in -= (IS_JET3(mdb)) ? 1 : 2;
 		*out_ptr++ = '?';
 		len_out--;
 	}
@@ -139,7 +139,7 @@ mdb_ascii2unicode(MdbHandle *mdb, char *src, size_t slen, char *dest, size_t dle
 #endif
 
 	/* Unicode Compression */
-	if(IS_JET4(mdb) && (dlen>4)) {
+	if(!IS_JET3(mdb) && (dlen>4)) {
 		unsigned char *tmp = g_malloc(dlen);
 		unsigned int tptr = 0, dptr = 0;
 		int comp = 1;
@@ -189,7 +189,7 @@ mdb_target_charset(MdbHandle *mdb)
 		iconv_code = "UTF-8";
 	return iconv_code;
 #else
-	if (IS_JET4(mdb))
+	if (!IS_JET3(mdb))
 		return "ISO-8859-1";
 	return NULL; // same as input: unknown
 #endif
@@ -205,7 +205,7 @@ void mdb_iconv_init(MdbHandle *mdb)
 	}
 
 #ifdef HAVE_ICONV
-	if (IS_JET4(mdb)) {
+	if (!IS_JET3(mdb)) {
 		mdb->iconv_out = iconv_open("UCS-2LE", iconv_code);
 		mdb->iconv_in = iconv_open(iconv_code, "UCS-2LE");
 	} else {
diff --git a/src/libmdb/index.c b/src/libmdb/index.c
index 73ab270..decca35 100644
--- a/src/libmdb/index.c
+++ b/src/libmdb/index.c
@@ -76,14 +76,14 @@ mdb_read_indices(MdbTableDef *table)
 
 	table->indices = g_ptr_array_new();
 
-	if (IS_JET4(mdb)) {
-		cur_pos = table->index_start + 52 * table->num_real_idxs;
-		idx2_sz = 28;
-		type_offset = 23;
-	} else {
+	if (IS_JET3(mdb)) {
 		cur_pos = table->index_start + 39 * table->num_real_idxs;
 		idx2_sz = 20;
 		type_offset = 19;
+	} else {
+		cur_pos = table->index_start + 52 * table->num_real_idxs;
+		idx2_sz = 28;
+		type_offset = 23;
 	}
 
 	//fprintf(stderr, "num_idxs:%d num_real_idxs:%d\n", table->num_idxs, table->num_real_idxs);
@@ -117,10 +117,10 @@ mdb_read_indices(MdbTableDef *table)
 
 	for (i=0;i<table->num_idxs;i++) {
 		pidx = g_ptr_array_index (table->indices, i);
-		if (IS_JET4(mdb)) {
-			name_sz=read_pg_if_16(mdb, &cur_pos);
-		} else {
+		if (IS_JET3(mdb)) {
 			name_sz=read_pg_if_8(mdb, &cur_pos);
+		} else {
+			name_sz=read_pg_if_16(mdb, &cur_pos);
 		}
 		tmpbuf = g_malloc(name_sz);
 		read_pg_if_n(mdb, tmpbuf, &cur_pos, name_sz);
@@ -133,7 +133,7 @@ mdb_read_indices(MdbTableDef *table)
 	mdb_read_pg(mdb, index_start_pg);
 	cur_pos = table->index_start;
 	for (i=0;i<table->num_real_idxs;i++) {
-		if (IS_JET4(mdb)) cur_pos += 4;
+		if (!IS_JET3(mdb)) cur_pos += 4;
 		/* look for index number i */
 		for (j=0; j<table->num_idxs; ++j) {
 			pidx = g_ptr_array_index (table->indices, j);
@@ -195,7 +195,7 @@ mdb_read_indices(MdbTableDef *table)
 		pidx->first_pg = read_pg_if_32(mdb, &cur_pos);
 		pidx->flags = read_pg_if_8(mdb, &cur_pos);
 		//fprintf(stderr, "pidx->first_pg:%d pidx->flags:0x%02x\n",	pidx->first_pg, pidx->flags);
-		if (IS_JET4(mdb)) cur_pos += 9;
+		if (!IS_JET3(mdb)) cur_pos += 9;
 	}
 	return NULL;
 }
diff --git a/src/libmdb/table.c b/src/libmdb/table.c
index c068195..bbbb00b 100644
--- a/src/libmdb/table.c
+++ b/src/libmdb/table.c
@@ -287,14 +287,10 @@ GPtrArray *mdb_read_columns(MdbTableDef *table)
 		char *tmp_buf;
 		pcol = g_ptr_array_index(table->columns, i);
 
-		if (IS_JET4(mdb)) {
-			name_sz = read_pg_if_16(mdb, &cur_pos);
-		} else if (IS_JET3(mdb)) {
+		if (IS_JET3(mdb))
 			name_sz = read_pg_if_8(mdb, &cur_pos);
-		} else {
-			fprintf(stderr,"Unknown MDB version\n");
-			continue;
-		}
+		else
+			name_sz = read_pg_if_16(mdb, &cur_pos);
 		tmp_buf = (char *) g_malloc(name_sz);
 		read_pg_if_n(mdb, tmp_buf, &cur_pos, name_sz);
 		mdb_unicode2ascii(mdb, tmp_buf, name_sz, pcol->name, MDB_MAX_OBJ_NAME);
diff --git a/src/libmdb/write.c b/src/libmdb/write.c
index 5b919b4..c1c93f0 100644
--- a/src/libmdb/write.c
+++ b/src/libmdb/write.c
@@ -172,12 +172,12 @@ mdb_crack_row(MdbTableDef *table, int row_start, int row_end, MdbField *fields)
 		mdb_buffer_dump(pg_buf, row_start, row_end - row_start + 1);
 	}
 
-	if (IS_JET4(mdb)) {
-		row_cols = mdb_get_int16(pg_buf, row_start);
-		col_count_size = 2;
-	} else {
+	if (IS_JET3(mdb)) {
 		row_cols = mdb_get_byte(pg_buf, row_start);
 		col_count_size = 1;
+	} else {
+		row_cols = mdb_get_int16(pg_buf, row_start);
+		col_count_size = 2;
 	}
 
 	bitmask_sz = (row_cols + 7) / 8;
@@ -185,15 +185,15 @@ mdb_crack_row(MdbTableDef *table, int row_start, int row_end, MdbField *fields)
 
 	/* read table of variable column locations */
 	if (table->num_var_cols > 0) {
-		row_var_cols = IS_JET4(mdb) ?
-			mdb_get_int16(pg_buf, row_end - bitmask_sz - 1) :
-			mdb_get_byte(pg_buf, row_end - bitmask_sz);
+		row_var_cols = IS_JET3(mdb) ?
+			mdb_get_byte(pg_buf, row_end - bitmask_sz) :
+			mdb_get_int16(pg_buf, row_end - bitmask_sz - 1);
 		var_col_offsets = (unsigned int *)g_malloc((row_var_cols+1)*sizeof(int));
-		if (IS_JET4(mdb)) {
-			mdb_crack_row4(mdb, row_start, row_end, bitmask_sz,
+		if (IS_JET3(mdb)) {
+			mdb_crack_row3(mdb, row_start, row_end, bitmask_sz,
 				 row_var_cols, var_col_offsets);
 		} else {
-			mdb_crack_row3(mdb, row_start, row_end, bitmask_sz,
+			mdb_crack_row4(mdb, row_start, row_end, bitmask_sz,
 				 row_var_cols, var_col_offsets);
 		}
 	}
@@ -415,10 +415,10 @@ mdb_pack_row(MdbTableDef *table, unsigned char *row_buffer, int unsigned num_fie
 			}
 		}
 	}
-	if (IS_JET4(table->entry->mdb)) {
-		return mdb_pack_row4(table, row_buffer, num_fields, fields);
-	} else {
+	if (IS_JET3(table->entry->mdb)) {
 		return mdb_pack_row3(table, row_buffer, num_fields, fields);
+	} else {
+		return mdb_pack_row4(table, row_buffer, num_fields, fields);
 	}
 }
 int
diff --git a/src/util/mdb-ver.c b/src/util/mdb-ver.c
index d1c66bc..c89a2b9 100644
--- a/src/util/mdb-ver.c
+++ b/src/util/mdb-ver.c
@@ -70,6 +70,8 @@ main(int argc, char **argv)
 		printf("JET3\n");
 	} else if (IS_JET4(mdb)) {
 		printf("JET4\n");
+	} else if (IS_JET5(mdb)) {
+		printf("JET5\n");
 	} else {
 		printf(_("unknown database version\n"));
 	}