diff --git a/offlineimap.conf b/offlineimap.conf
index cf2776c..a730484 100644
--- a/offlineimap.conf
+++ b/offlineimap.conf
@@ -540,6 +540,7 @@ localfolders = ~/Test
 #
 #filename_use_mail_timestamp = no
 
+
 # This option stands in the [Repository LocalExample] section.
 #
 # Map IMAP [user-defined] keywords to lowercase letters, similar to Dovecot's
diff --git a/offlineimap/accounts.py b/offlineimap/accounts.py
index 45fddfc..46671c1 100644
--- a/offlineimap/accounts.py
+++ b/offlineimap/accounts.py
@@ -453,15 +453,10 @@ def syncfolder(account, remotefolder, quick):
             localfolder.save_uidvalidity()
             remotefolder.save_uidvalidity()
 
-    def save_min_uid(folder, min_uid):
-        uidfile = folder.get_min_uid_file()
-        fd = open(uidfile, 'wt')
-        fd.write(str(min_uid) + "\n")
-        fd.close()
-
-    def cachemessagelists_upto_date(localfolder, remotefolder, date):
+    def cachemessagelists_upto_date(date):
         """Returns messages with uid > min(uids of messages newer than date)."""
 
+        # Warning: this makes sense only if the cached list is empty.
         localfolder.cachemessagelist(min_date=date)
         check_uid_validity(localfolder, remotefolder, statusfolder)
         # Local messagelist had date restriction applied already. Restrict
@@ -515,7 +510,7 @@ def syncfolder(account, remotefolder, quick):
                     min_uid = min(positive_uids)
                 else:
                     min_uid = 1
-                save_min_uid(partial, min_uid)
+                partial.save_min_uid(min_uid)
         else:
             partial.cachemessagelist(min_uid=min_uid)
 
@@ -562,7 +557,7 @@ def syncfolder(account, remotefolder, quick):
             ui.warn("Quick syncs (-q) not supported in conjunction "
                 "with maxage or startdate; ignoring -q.")
         if maxage != None:
-            cachemessagelists_upto_date(localfolder, remotefolder, maxage)
+            cachemessagelists_upto_date(maxage)
         elif localstart != None:
             cachemessagelists_startdate(remotefolder, localfolder,
                 localstart)
diff --git a/offlineimap/folder/Base.py b/offlineimap/folder/Base.py
index 4b2b78b..5f287fa 100644
--- a/offlineimap/folder/Base.py
+++ b/offlineimap/folder/Base.py
@@ -400,6 +400,12 @@ class BaseFolder(object):
             os.mkdir(startuiddir, 0o700)
         return os.path.join(startuiddir, self.getfolderbasename())
 
+    def save_min_uid(self, min_uid):
+        uidfile = self.get_min_uid_file()
+        fd = open(uidfile, 'wt')
+        fd.write(str(min_uid) + "\n")
+        fd.close()
+
     def retrieve_min_uid(self):
         uidfile = self.get_min_uid_file()
         if not os.path.exists(uidfile):
diff --git a/offlineimap/folder/LocalStatusSQLite.py b/offlineimap/folder/LocalStatusSQLite.py
index d172f58..47c7144 100644
--- a/offlineimap/folder/LocalStatusSQLite.py
+++ b/offlineimap/folder/LocalStatusSQLite.py
@@ -91,7 +91,6 @@ class LocalStatusSQLiteFolder(BaseFolder):
         if self.filename not in LocalStatusSQLiteFolder.locks:
             LocalStatusSQLiteFolder.locks[self.filename] = DatabaseFileLock()
         self._databaseFileLock = LocalStatusSQLiteFolder.locks[self.filename]
-
         self._in_transactions = 0
 
     def __enter__(self):
diff --git a/offlineimap/folder/Maildir.py b/offlineimap/folder/Maildir.py
index e00e727..7998912 100644
--- a/offlineimap/folder/Maildir.py
+++ b/offlineimap/folder/Maildir.py
@@ -34,14 +34,16 @@ except NameError:
 from offlineimap import OfflineImapError, emailutil
 from .Base import BaseFolder
 
+
 # Find the UID in a message filename
 re_uidmatch = re.compile(',U=(\d+)')
 # Find a numeric timestamp in a string (filename prefix)
-re_timestampmatch = re.compile('(\d+)');
+re_timestampmatch = re.compile('(\d+)')
 
 timehash = {}
 timelock = Lock()
 
+
 def _gettimeseq(date=None):
     global timehash, timelock
     timelock.acquire()
@@ -56,6 +58,7 @@ def _gettimeseq(date=None):
     finally:
         timelock.release()
 
+
 class MaildirFolder(BaseFolder):
     def __init__(self, root, name, sep, repository):
         self.sep = sep # needs to be set before super().__init__
@@ -343,6 +346,7 @@ class MaildirFolder(BaseFolder):
         See folder/Base for detail. Note that savemessage() does not
         check against dryrun settings, so you need to ensure that
         savemessage is never called in a dryrun mode."""
+
         # This function only ever saves to tmp/,
         # but it calls savemessageflags() to actually save to cur/ or new/.
         self.ui.savemessage('maildir', uid, flags, self)
@@ -471,6 +475,8 @@ class MaildirFolder(BaseFolder):
         oldfilename = self.messagelist[uid]['filename']
         dir_prefix, filename = os.path.split(oldfilename)
         flags = self.getmessageflags(uid)
+        # TODO: we aren't keeping the prefix timestamp so we don't honor the
+        # filename_use_mail_timestamp configuration option.
         newfilename = os.path.join(dir_prefix,
           self.new_message_filename(new_uid, flags))
         os.rename(os.path.join(self.getfullname(), oldfilename),