diff --git a/README.md b/README.md
index b8e3f4b..890265b 100644
--- a/README.md
+++ b/README.md
@@ -132,8 +132,9 @@ customize the output. The formatter takes four values:
 
 * tag -- the name of the current element with '=' or an empty string in case of array index,
 * head -- an opening table bracket `{` and associated indentation and newline (if any),
-* body -- table elements concatenated into a string using commas and indentation/newlines (if any), and
-* tail -- a closing table bracket `}` and associated indentation and newline (if any).
+* body -- table elements concatenated into a string using commas and indentation/newlines (if any),
+* tail -- a closing table bracket `}` and associated indentation and newline (if any), and
+* level -- the current level.
 
 For example, the following call will apply
 `Foo{bar} notation to its output (used by Metalua to display ASTs):
diff --git a/src/serpent.lua b/src/serpent.lua
index 297cec7..c5e862b 100644
--- a/src/serpent.lua
+++ b/src/serpent.lua
@@ -1,4 +1,4 @@
-local n, v = "serpent", 0.288 -- (C) 2012-17 Paul Kulchenko; MIT License
+local n, v = "serpent", 0.289 -- (C) 2012-17 Paul Kulchenko; MIT License
 local c, d = "Paul Kulchenko", "Lua serializer and pretty printer"
 local snum = {[tostring(1/0)]='1/0 --[[math.huge]]',[tostring(-1/0)]='-1/0 --[[-math.huge]]',[tostring(0/0)]='0/0'}
 local badtype = {thread = true, userdata = true, cdata = true}
@@ -99,7 +99,7 @@ local function s(t, opts)
       local head = indent and '{\n'..prefix..indent or '{'
       local body = table.concat(out, ','..(indent and '\n'..prefix..indent or space))
       local tail = indent and "\n"..prefix..'}' or '}'
-      return (custom and custom(tag,head,body,tail) or tag..head..body..tail)..comment(t, level)
+      return (custom and custom(tag,head,body,tail,level) or tag..head..body..tail)..comment(t, level)
     elseif badtype[ttype] then
       seen[t] = insref or spath
       return tag..globerr(t, level)