diff --git a/CHANGES b/CHANGES
--- a/CHANGES
+++ b/CHANGES
@@ -1,6 +1,11 @@
 User-visible changes in hledger-web. See also hledger, hledger-lib.
 
 
+# 1.9.1 (2018/4/13)
+
+* fix compilation with yesod < 1.6
+
+
 # 1.9 (2018/3/31)
 
 * support ghc 8.4, latest deps
diff --git a/Foundation.hs b/Foundation.hs
--- a/Foundation.hs
+++ b/Foundation.hs
@@ -92,7 +92,11 @@
 -- | A convenience alias.
 type AppRoute = Route App
 
+#if MIN_VERSION_yesod(1,6,0)
 type Form x = Html -> MForm (HandlerFor App) (FormResult x, Widget)
+#else
+type Form x = Html -> MForm (HandlerT App IO) (FormResult x, Widget)
+#endif
 
 -- Please see the documentation for the Yesod typeclass. There are a number
 -- of settings which can be configured by overriding methods here.
diff --git a/Handler/Common.hs b/Handler/Common.hs
--- a/Handler/Common.hs
+++ b/Handler/Common.hs
@@ -28,7 +28,11 @@
 -- Common page layout
 
 -- | Standard hledger-web page layout.
+#if MIN_VERSION_yesod(1,6,0)
 hledgerLayout :: ViewData -> String -> HtmlUrl AppRoute -> HandlerFor App Html
+#else
+hledgerLayout :: ViewData -> String -> HtmlUrl AppRoute -> HandlerT App IO Html
+#endif
 hledgerLayout vd title content = do
   defaultLayout $ do
       setTitle $ toHtml $ title ++ " - hledger-web"
diff --git a/hledger-web.1 b/hledger-web.1
--- a/hledger-web.1
+++ b/hledger-web.1
@@ -1,5 +1,5 @@
 
-.TH "hledger\-web" "1" "March 2018" "hledger\-web 1.9" "hledger User Manuals"
+.TH "hledger\-web" "1" "April 2018" "hledger\-web 1.9.1" "hledger User Manuals"
 
 
 
diff --git a/hledger-web.cabal b/hledger-web.cabal
--- a/hledger-web.cabal
+++ b/hledger-web.cabal
@@ -1,11 +1,11 @@
--- This file has been generated from package.yaml by hpack version 0.20.0.
+-- This file has been generated from package.yaml by hpack version 0.28.2.
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 9bcbee0a35b7edb9342cc7f08113385a491beb872a21b2f157a65106c4dea4dd
+-- hash: ff770abdfef6363c5943add80204995ba6d7bd67d15564d2d1089f37c79b66b5
 
 name:           hledger-web
-version:        1.9
+version:        1.9.1
 synopsis:       Web interface for the hledger accounting tool
 description:    This is hledger's web interface.
                 It provides a more user-friendly and collaborative UI than the
@@ -28,7 +28,6 @@
 tested-with:    GHC==7.10.3, GHC==8.0.2, GHC==8.2.1
 build-type:     Simple
 cabal-version:  >= 1.10
-
 extra-source-files:
     CHANGES
     config/favicon.ico
@@ -122,7 +121,7 @@
 
 library
   ghc-options: -Wall -fno-warn-unused-do-bind -fno-warn-name-shadowing -fno-warn-missing-signatures -fno-warn-type-defaults -fno-warn-orphans
-  cpp-options: -DVERSION="1.9"
+  cpp-options: -DVERSION="1.9.1"
   build-depends:
       HUnit
     , base >=4.8 && <4.12
@@ -190,7 +189,7 @@
   hs-source-dirs:
       app
   ghc-options: -Wall -fno-warn-unused-do-bind -fno-warn-name-shadowing -fno-warn-missing-signatures -fno-warn-type-defaults -fno-warn-orphans
-  cpp-options: -DVERSION="1.9"
+  cpp-options: -DVERSION="1.9.1"
   build-depends:
       HUnit
     , base >=4.8 && <4.12
@@ -247,7 +246,7 @@
   hs-source-dirs:
       tests
   ghc-options: -Wall -fno-warn-unused-do-bind -fno-warn-name-shadowing -fno-warn-missing-signatures -fno-warn-type-defaults -fno-warn-orphans
-  cpp-options: -DVERSION="1.9"
+  cpp-options: -DVERSION="1.9.1"
   build-depends:
       HUnit
     , base >=4.8 && <4.12
diff --git a/hledger-web.info b/hledger-web.info
--- a/hledger-web.info
+++ b/hledger-web.info
@@ -3,8 +3,8 @@
 
 File: hledger-web.info,  Node: Top,  Next: OPTIONS,  Up: (dir)
 
-hledger-web(1) hledger-web 1.9
-******************************
+hledger-web(1) hledger-web 1.9.1
+********************************
 
 hledger-web is hledger's web interface.  It starts a simple web
 application for browsing and adding transactions, and optionally opens
@@ -209,7 +209,7 @@
 
 Tag Table:
 Node: Top72
-Node: OPTIONS3152
-Ref: #options3237
+Node: OPTIONS3156
+Ref: #options3241
 
 End Tag Table
diff --git a/hledger-web.txt b/hledger-web.txt
--- a/hledger-web.txt
+++ b/hledger-web.txt
@@ -248,4 +248,4 @@
 
 
 
-hledger-web 1.9                   March 2018                    hledger-web(1)
+hledger-web 1.9.1                 April 2018                    hledger-web(1)