diff --git a/changes/bug4012 b/changes/bug4012
new file mode 100644
index 0000000000..082f39df93
--- /dev/null
+++ b/changes/bug4012
@@ -0,0 +1,8 @@
+  o Minor bugfixes (documentation):
+    - Add missing documentation for the MaxClientCircuitsPending,
+      UseMicrodescriptors, UserspaceIOCPBuffers, and
+      _UseFilteringSSLBufferevents options, all introduced during
+      the 0.2.3.x series.
+
+
+
diff --git a/doc/tor.1.txt b/doc/tor.1.txt
index 5ac2ba0c7b..37151712f1 100644
--- a/doc/tor.1.txt
+++ b/doc/tor.1.txt
@@ -487,6 +487,21 @@ Other options can be specified either on the command-line (--option
     and you're running on Windows, setting this option to 1 will tell Libevent
     not to use the Windows IOCP networking API.  (Default: 1)
 
+**UserspaceIOCPBuffers** **0**|**1**::
+    If IOCP is enabled (see DisableIOCP above), setting this option to 1
+    will tell Tor to disable kernel-space TCP buffers, in order to avoid
+    needless copy operations and try not to run out of non-paged RAM.
+    This feature is experimental; don't use it yet unless you're eager to
+    help tracking down bugs. (Default: 0)
+
+**_UseFilteringSSLBufferevents** **0**|**1**::
+    Tells Tor to do its SSL communication using a chain of
+    bufferevents: one for SSL and one for networking.  This option has no
+    effect if bufferevents are disabled (in which case it can't turn on), or
+    if IOCP bufferevents are enabled (in which case it can't turn off).  This
+    option is useful for debugging only; most users shouldn't touch it.
+    (Default: 0)
+
 **CountPrivateBandwidth** **0**|**1**::
     If this option is set, then Tor's rate-limiting applies not only to
     remote connections, but also to connections to private addresses like
@@ -757,6 +772,11 @@ The following options are useful only for clients (that is, if
     but never attach a new stream to a circuit that is too old. (Default: 10
     minutes)
 
+**MaxClientCircuitsPending** __NUM__::
+    Do not allow more than NUM circuits to be pending at a time for handling
+    client streams. A circuit is pending if we have begun constructing it,
+    but it has not yet been completely constructed.  (Default: 32)
+
 **NodeFamily** __node__,__node__,__...__::
     The Tor servers, defined by their identity fingerprints or nicknames,
     constitute a "family" of similar or co-administered servers, so never use
@@ -1042,6 +1062,15 @@ The following options are useful only for clients (that is, if
     To enable this option the compile time flag --enable-tor2webmode must be
     specified. (Default: 0)
 
+**UseMicrodescriptors** **0**|**1**|**auto**::
+    Microdescriptors are a smaller version of the information that Tor needs
+    in order to build its circuits.  Using microdescriptors makes Tor clients
+    download less directory information, thus saving bandwidth.  Directory
+    caches need to fetch regular descriptors and microdescriptors, so this
+    option doesn't save any bandwidth for them.  If this option is set to
+    "auto" (recommended) then it is on for all clients that do not set
+    FetchUselessDescriptors. (Default: auto)
+
 SERVER OPTIONS
 --------------