diff --git a/rocksdb/_rocksdb.pyx b/rocksdb/_rocksdb.pyx
index 697651bb1cf91e5a6660bdb47af2d0a0814c9c34..9ae4feaf1c47e4f0a458568f3b0851d77a33c57e 100644
--- a/rocksdb/_rocksdb.pyx
+++ b/rocksdb/_rocksdb.pyx
@@ -1072,24 +1072,6 @@ cdef class ColumnFamilyOptions(object):
         def __set__(self, value):
             self.copts.max_bytes_for_level_multiplier_additional = value
 
-    property soft_rate_limit:
-        def __get__(self):
-            return self.copts.soft_rate_limit
-        def __set__(self, value):
-            self.copts.soft_rate_limit = value
-
-    property hard_rate_limit:
-        def __get__(self):
-            return self.copts.hard_rate_limit
-        def __set__(self, value):
-            self.copts.hard_rate_limit = value
-
-    property rate_limit_delay_max_milliseconds:
-        def __get__(self):
-            return self.copts.rate_limit_delay_max_milliseconds
-        def __set__(self, value):
-            self.copts.rate_limit_delay_max_milliseconds = value
-
     property arena_block_size:
         def __get__(self):
             return self.copts.arena_block_size
@@ -1102,12 +1084,6 @@ cdef class ColumnFamilyOptions(object):
         def __set__(self, value):
             self.copts.disable_auto_compactions = value
 
-    property purge_redundant_kvs_while_flush:
-        def __get__(self):
-            return self.copts.purge_redundant_kvs_while_flush
-        def __set__(self, value):
-            self.copts.purge_redundant_kvs_while_flush = value
-
     # FIXME: remove to util/options_helper.h
     #  property allow_os_buffer:
         #  def __get__(self):
@@ -1455,12 +1431,6 @@ cdef class Options(ColumnFamilyOptions):
         def __set__(self, value):
             self.opts.is_fd_close_on_exec = value
 
-    property skip_log_error_on_recovery:
-        def __get__(self):
-            return self.opts.skip_log_error_on_recovery
-        def __set__(self, value):
-            self.opts.skip_log_error_on_recovery = value
-
     property stats_dump_period_sec:
         def __get__(self):
             return self.opts.stats_dump_period_sec
diff --git a/rocksdb/backup.pxd b/rocksdb/backup.pxd
index 1271c730a61152060074037ad5c92ea4bef0f0c0..9efbb58b398b98d824b748154f95688299c99dde 100644
--- a/rocksdb/backup.pxd
+++ b/rocksdb/backup.pxd
@@ -9,9 +9,11 @@ from .status cimport Status
 from .db cimport DB
 from .env cimport Env
 
+# TODO: For rocksdb >= 6.21.0, change to `rocksdb/utilities/backup_engine.h`.
 cdef extern from "rocksdb/utilities/backupable_db.h" namespace "rocksdb":
     ctypedef uint32_t BackupID
 
+    # TODO: For rocksdb >= 6.21.0, rename to `BackupEngineOptions`.
     cdef cppclass BackupableDBOptions:
         BackupableDBOptions(const string& backup_dir)
 
@@ -29,6 +31,7 @@ cdef extern from "rocksdb/utilities/backupable_db.h" namespace "rocksdb":
         Status RestoreDBFromBackup(BackupID, string&, string&) nogil except+
         Status RestoreDBFromLatestBackup(string&, string&) nogil except+
 
+    # TODO: For rocksdb >= 6.21.0, swap order of first two parameters.
     cdef Status BackupEngine_Open "rocksdb::BackupEngine::Open"(
             Env*,
             BackupableDBOptions&,