diff --git a/libraries/liblmdb/CHANGES b/libraries/liblmdb/CHANGES
index 957742e752..b35ca61d76 100644
--- a/libraries/liblmdb/CHANGES
+++ b/libraries/liblmdb/CHANGES
@@ -1,5 +1,7 @@
 LMDB 0.9 Change Log
 
+LMDB 0.9.16 Release Engineering
+
 LMDB 0.9.15 Release (2015/06/19)
 	Fix txn init (ITS#7961,#7987)
 	Fix MDB_PREV_DUP (ITS#7955,#7671)
diff --git a/libraries/liblmdb/lmdb.h b/libraries/liblmdb/lmdb.h
index 2f523579c8..e935509d9e 100644
--- a/libraries/liblmdb/lmdb.h
+++ b/libraries/liblmdb/lmdb.h
@@ -413,7 +413,14 @@ typedef enum MDB_cursor_op {
 #define MDB_PAGE_FULL	(-30786)
 	/** Database contents grew beyond environment mapsize */
 #define MDB_MAP_RESIZED	(-30785)
-	/** MDB_INCOMPATIBLE: Operation and DB incompatible, or DB flags changed */
+	/** Operation and DB incompatible, or DB type changed. This can mean:
+	 *	<ul>
+	 *	<li>The operation expects an #MDB_DUPSORT / #MDB_DUPFIXED database.
+	 *	<li>Opening a named DB when the unnamed DB has #MDB_DUPSORT / #MDB_INTEGERKEY.
+	 *	<li>Accessing a data record as a database, or vice versa.
+	 *	<li>The database was dropped and recreated with different flags.
+	 *	</ul>
+	 */
 #define MDB_INCOMPATIBLE	(-30784)
 	/** Invalid reuse of reader locktable slot */
 #define MDB_BAD_RSLOT		(-30783)
@@ -1034,8 +1041,9 @@ int  mdb_txn_renew(MDB_txn *txn);
 	 * any other transaction in the process may use this function.
 	 *
 	 * To use named databases (with name != NULL), #mdb_env_set_maxdbs()
-	 * must be called before opening the environment.  Database names
-	 * are kept as keys in the unnamed database.
+	 * must be called before opening the environment.  Database names are
+	 * keys in the unnamed database, and may be read but not written.
+	 *
 	 * @param[in] txn A transaction handle returned by #mdb_txn_begin()
 	 * @param[in] name The name of the database to open. If only a single
 	 * 	database is needed in the environment, this value may be NULL.
diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index 6bdf3151dc..adc20f893b 100644
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -2822,8 +2822,8 @@ mdb_txn_reset0(MDB_txn *txn, const char *act)
 		}
 
 		if (!txn->mt_parent) {
-			if (mdb_midl_shrink(&txn->mt_free_pgs))
-				env->me_free_pgs = txn->mt_free_pgs;
+			mdb_midl_shrink(&txn->mt_free_pgs);
+			env->me_free_pgs = txn->mt_free_pgs;
 			/* me_pgstate: */
 			env->me_pghead = NULL;
 			env->me_pglast = 0;
@@ -3395,7 +3395,8 @@ mdb_txn_commit(MDB_txn *txn)
 					goto fail;
 				}
 				data.mv_data = &txn->mt_dbs[i];
-				rc = mdb_cursor_put(&mc, &txn->mt_dbxs[i].md_name, &data, 0);
+				rc = mdb_cursor_put(&mc, &txn->mt_dbxs[i].md_name, &data,
+					F_SUBDATA);
 				if (rc)
 					goto fail;
 			}
@@ -3408,8 +3409,8 @@ mdb_txn_commit(MDB_txn *txn)
 
 	mdb_midl_free(env->me_pghead);
 	env->me_pghead = NULL;
-	if (mdb_midl_shrink(&txn->mt_free_pgs))
-		env->me_free_pgs = txn->mt_free_pgs;
+	mdb_midl_shrink(&txn->mt_free_pgs);
+	env->me_free_pgs = txn->mt_free_pgs;
 
 #if (MDB_DEBUG) > 2
 	mdb_audit(txn);
@@ -5214,6 +5215,8 @@ mdb_page_search(MDB_cursor *mc, MDB_val *key, int flags)
 						&mc->mc_dbx->md_name, &exact);
 					if (!exact)
 						return MDB_NOTFOUND;
+					if ((leaf->mn_flags & (F_DUPDATA|F_SUBDATA)) != F_SUBDATA)
+						return MDB_INCOMPATIBLE; /* not a named DB */
 					rc = mdb_node_read(mc->mc_txn, leaf, &data);
 					if (rc)
 						return rc;
@@ -5725,8 +5728,10 @@ set2:
 
 	if (leaf == NULL) {
 		DPUTS("===> inexact leaf not found, goto sibling");
-		if ((rc = mdb_cursor_sibling(mc, 1)) != MDB_SUCCESS)
+		if ((rc = mdb_cursor_sibling(mc, 1)) != MDB_SUCCESS) {
+			mc->mc_flags |= C_EOF;
 			return rc;		/* no entries matched */
+		}
 		mp = mc->mc_pg[mc->mc_top];
 		mdb_cassert(mc, IS_LEAF(mp));
 		leaf = NODEPTR(mp, 0);
@@ -6404,6 +6409,9 @@ prep_subDB:
 			goto new_sub;
 		}
 current:
+		/* LMDB passes F_SUBDATA in 'flags' to write a DB record */
+		if ((leaf->mn_flags ^ flags) & F_SUBDATA)
+			return MDB_INCOMPATIBLE;
 		/* overflow page overwrites need special handling */
 		if (F_ISSET(leaf->mn_flags, F_BIGDATA)) {
 			MDB_page *omp;
@@ -6674,6 +6682,11 @@ mdb_cursor_del(MDB_cursor *mc, unsigned int flags)
 				goto fail;
 		}
 	}
+	/* LMDB passes F_SUBDATA in 'flags' to delete a DB record */
+	else if ((leaf->mn_flags ^ flags) & F_SUBDATA) {
+		rc = MDB_INCOMPATIBLE;
+		goto fail;
+	}
 
 	/* add overflow pages to free list */
 	if (F_ISSET(leaf->mn_flags, F_BIGDATA)) {
@@ -9169,7 +9182,7 @@ int mdb_dbi_open(MDB_txn *txn, const char *name, unsigned int flags, MDB_dbi *db
 	if (rc == MDB_SUCCESS) {
 		/* make sure this is actually a DB */
 		MDB_node *node = NODEPTR(mc.mc_pg[mc.mc_top], mc.mc_ki[mc.mc_top]);
-		if (!(node->mn_flags & F_SUBDATA))
+		if ((node->mn_flags & (F_DUPDATA|F_SUBDATA)) != F_SUBDATA)
 			return MDB_INCOMPATIBLE;
 	} else if (rc == MDB_NOTFOUND && (flags & MDB_CREATE)) {
 		/* Create if requested */
@@ -9362,7 +9375,7 @@ int mdb_drop(MDB_txn *txn, MDB_dbi dbi, int del)
 
 	/* Can't delete the main DB */
 	if (del && dbi > MAIN_DBI) {
-		rc = mdb_del0(txn, MAIN_DBI, &mc->mc_dbx->md_name, NULL, 0);
+		rc = mdb_del0(txn, MAIN_DBI, &mc->mc_dbx->md_name, NULL, F_SUBDATA);
 		if (!rc) {
 			txn->mt_dbflags[dbi] = DB_STALE;
 			mdb_dbi_close(txn->mt_env, dbi);
diff --git a/libraries/liblmdb/midl.c b/libraries/liblmdb/midl.c
index 16782dcafc..57a9d4920e 100644
--- a/libraries/liblmdb/midl.c
+++ b/libraries/liblmdb/midl.c
@@ -116,7 +116,7 @@ void mdb_midl_free(MDB_IDL ids)
 		free(ids-1);
 }
 
-int mdb_midl_shrink( MDB_IDL *idp )
+void mdb_midl_shrink( MDB_IDL *idp )
 {
 	MDB_IDL ids = *idp;
 	if (*(--ids) > MDB_IDL_UM_MAX &&
@@ -124,9 +124,7 @@ int mdb_midl_shrink( MDB_IDL *idp )
 	{
 		*ids++ = MDB_IDL_UM_MAX;
 		*idp = ids;
-		return 1;
 	}
-	return 0;
 }
 
 static int mdb_midl_grow( MDB_IDL *idp, int num )
diff --git a/libraries/liblmdb/midl.h b/libraries/liblmdb/midl.h
index 9b041d72d1..2331e78398 100644
--- a/libraries/liblmdb/midl.h
+++ b/libraries/liblmdb/midl.h
@@ -98,9 +98,8 @@ void mdb_midl_free(MDB_IDL ids);
 	/** Shrink an IDL.
 	 * Return the IDL to the default size if it has grown larger.
 	 * @param[in,out] idp	Address of the IDL to shrink.
-	 * @return	0 on no change, non-zero if shrunk.
 	 */
-int mdb_midl_shrink(MDB_IDL *idp);
+void mdb_midl_shrink(MDB_IDL *idp);
 
 	/** Make room for num additional elements in an IDL.
 	 * @param[in,out] idp	Address of the IDL.