diff --git a/CHANGES b/CHANGES
index d1ac8e15..aae4ad10 100644
--- a/CHANGES
+++ b/CHANGES
@@ -4,12 +4,16 @@ LMDB 0.9.18 Release Engineering
 	Add MDB_PREV_MULTIPLE
 	already done for mdbx - Fix robust mutex detection on glibc 2.10-11 (ITS#8330)
 	Fix page_search_root assert on FreeDB (ITS#8336)
+	Fix MDB_APPENDDUP vs. rewrite(single item) (ITS#8334)
+	n/a for mdbx - Fix mdb_copy of large files on Windows
+	Fix subcursor move after delete (ITS#8355)
 	n/a for mdbx - Check for utf8_to_utf16 failures (ITS#7992)
 	Catch strdup failure in mdb_dbi_open
 	Build
 		already done for mdbx - Additional makefile var tweaks (ITS#8169)
 	Documentation
 		Add Getting Started page
+		Update WRITEMAP description
 
 
 LMDB 0.9.17 Release (2015/11/30)
diff --git a/lmdb.h b/lmdb.h
index 4aa8de13..4250795e 100644
--- a/lmdb.h
+++ b/lmdb.h
@@ -554,9 +554,11 @@ int  mdb_env_create(MDB_env **env);
 	 *		allowed. LMDB will still modify the lock file - except on read-only
 	 *		filesystems, where LMDB does not use locks.
 	 *	<li>#MDB_WRITEMAP
-	 *		Use a writeable memory map unless MDB_RDONLY is set. This is faster
-	 *		and uses fewer mallocs, but loses protection from application bugs
+	 *		Use a writeable memory map unless MDB_RDONLY is set. This uses
+	 *		fewer mallocs but loses protection from application bugs
 	 *		like wild pointer writes and other bad updates into the database.
+	 *		This may be slightly faster for DBs that fit entirely in RAM, but
+	 *		is slower for DBs larger than RAM.
 	 *		Incompatible with nested transactions.
 	 *		Do not mix processes with and without MDB_WRITEMAP on the same
 	 *		environment.  This can defeat durability (#mdb_env_sync etc).
diff --git a/mdb.c b/mdb.c
index 62a2a8fb..9bb87c5a 100644
--- a/mdb.c
+++ b/mdb.c
@@ -4511,16 +4511,12 @@ static pthread_mutex_t mdb_rthc_lock = PTHREAD_MUTEX_INITIALIZER;
 
 /* LY: TODO: Yet another problem is here - segfault in case if a DSO will
  * be unloaded before a thread would been finished. */
-static void
-mdb_env_reader_destr(void *ptr)
+static ATTRIBUTE_NO_SANITIZE_THREAD
+void mdb_env_reader_destr(void *ptr)
 {
 	struct MDB_rthc* rthc = ptr;
 	MDB_reader *reader;
 
-	if (! rthc)
-		/* LY: paranoia */
-		return;
-
 	mdb_ensure(NULL, pthread_mutex_lock(&mdb_rthc_lock) == 0);
 	reader = rthc->rc_reader;
 	if (reader && reader->mr_pid == getpid()) {
@@ -5818,8 +5814,10 @@ mdb_cursor_next(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op)
 
 	mdb_debug("cursor_next: top page is %zu in cursor %p",
 		mdb_dbg_pgno(mp), (void *) mc);
-	if (mc->mc_flags & C_DEL)
+	if (mc->mc_flags & C_DEL) {
+		mc->mc_flags ^= C_DEL;
 		goto skip;
+	}
 
 	if (mc->mc_ki[mc->mc_top] + 1u >= NUMKEYS(mp)) {
 		mdb_debug("=====> move to next sibling page");
@@ -5898,6 +5896,8 @@ mdb_cursor_prev(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op)
 	mdb_debug("cursor_prev: top page is %zu in cursor %p",
 		mdb_dbg_pgno(mp), (void *) mc);
 
+	mc->mc_flags &= ~(C_EOF|C_DEL);
+
 	if (mc->mc_ki[mc->mc_top] == 0)  {
 		mdb_debug("=====> move to prev sibling page");
 		if ((rc = mdb_cursor_sibling(mc, 0)) != MDB_SUCCESS) {
@@ -5909,8 +5909,6 @@ mdb_cursor_prev(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op)
 	} else
 		mc->mc_ki[mc->mc_top]--;
 
-	mc->mc_flags &= ~C_EOF;
-
 	mdb_debug("==> cursor points to page %zu with %u keys, key index %u",
 		mdb_dbg_pgno(mp), NUMKEYS(mp), mc->mc_ki[mc->mc_top]);