Bug: stats.lua dfrom and dto parameters not doc

 This fixes #544
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1b758b7..b6cf115 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,5 @@
 ## Changes in 0.12:
+-  Bug: stats.lua dfrom and dto parameters are not documented in API (#544)
 - Bug: atom.lua is not documented (#538)
 - Bug: notifications.lua 'seen' option is not documented (#539)
 - Bug: &since option for stats.lua is not documented (#537)
diff --git a/docs/API.md b/docs/API.md
index d94ece3..7f39b19 100644
--- a/docs/API.md
+++ b/docs/API.md
@@ -41,7 +41,7 @@
 
 ### Fetching list data
 Usage:
-`GET /api/stats.lua?list=$list&domain=$domain[&d=$timespan][&q=$query][&header_from=$from][&header_to=$to][&header_subject=$subject][&header_body=$body][&quick][&emailsOnly][&s=$s&e=$e][&since=$since]`
+`GET /api/stats.lua?list=$list&domain=$domain[&d=$timespan][&q=$query][&header_from=$from][&header_to=$to][&header_subject=$subject][&header_body=$body][&quick][&emailsOnly][&s=$s&e=$e][&since=$since][&dfrom=$dfrom&dto=$dto]`
 
 Parameters:
 
@@ -60,6 +60,8 @@
     - $body: Optional body text
     - $since: number of seconds since the epoch, defaults to now. 
        Returns '{"changed":false}' if no emails are later than epoch, otherwise proceeds with normal search
+    - $dfrom: days ago to start
+    - $dto: total days to match
 
 Options: