diff --git a/CHANGELOG b/CHANGELOG
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,14 @@
+propellor (3.0.4) unstable; urgency=medium
+
+  * Run letsencrypt with --noninteractive.
+  * Fix build with ghc 8.0.1.
+    Thanks, davean.
+  * Module added for the Borg backup system.
+    Thanks, Félix Sipma.
+  * Fix build with directory-1.2.6.2.
+
+ -- Joey Hess <id@joeyh.name>  Sun, 22 May 2016 15:54:49 -0400
+
 propellor (3.0.3) unstable; urgency=medium
 
   * Remove Propellor.DotDir from the propellor library, as its use of
diff --git a/debian/changelog b/debian/changelog
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,14 @@
+propellor (3.0.4) unstable; urgency=medium
+
+  * Run letsencrypt with --noninteractive.
+  * Fix build with ghc 8.0.1.
+    Thanks, davean.
+  * Module added for the Borg backup system.
+    Thanks, Félix Sipma.
+  * Fix build with directory-1.2.6.2.
+
+ -- Joey Hess <id@joeyh.name>  Sun, 22 May 2016 15:54:49 -0400
+
 propellor (3.0.3) unstable; urgency=medium
 
   * Remove Propellor.DotDir from the propellor library, as its use of
diff --git a/debian/control b/debian/control
--- a/debian/control
+++ b/debian/control
@@ -20,7 +20,7 @@
 	libghc-text-dev,
 	libghc-concurrent-output-dev,
 Maintainer: Joey Hess <id@joeyh.name>
-Standards-Version: 3.9.6
+Standards-Version: 3.9.8
 Vcs-Git: git://git.joeyh.name/propellor
 Homepage: http://propellor.branchable.com/
 
diff --git a/propellor.cabal b/propellor.cabal
--- a/propellor.cabal
+++ b/propellor.cabal
@@ -1,7 +1,7 @@
 Name: propellor
-Version: 3.0.3
+Version: 3.0.4
 Cabal-Version: >= 1.8
-License: BSD3
+License: BSD2
 Maintainer: Joey Hess <id@joeyh.name>
 Author: Joey Hess
 Stability: Stable
@@ -81,6 +81,7 @@
     Propellor.Property.Apt
     Propellor.Property.Apt.PPA
     Propellor.Property.Attic
+    Propellor.Property.Borg
     Propellor.Property.Cmd
     Propellor.Property.Concurrent
     Propellor.Property.Conductor
@@ -206,6 +207,7 @@
     Utility.Process.NonConcurrent
     Utility.SafeCommand
     Utility.Scheduled
+    Utility.SystemDirectory
     Utility.Table
     Utility.ThreadScheduler
     Utility.Tmp
diff --git a/src/Propellor/Base.hs b/src/Propellor/Base.hs
--- a/src/Propellor/Base.hs
+++ b/src/Propellor/Base.hs
@@ -20,7 +20,7 @@
 	, module Propellor.Utilities
 
 	-- * System modules
-	, module System.Directory
+	, module Utility.SystemDirectory
 	, module System.IO
 	, module System.FilePath
 	, module Data.Maybe
@@ -47,7 +47,7 @@
 import Propellor.Location
 import Propellor.Utilities
 
-import System.Directory
+import Utility.SystemDirectory
 import System.IO
 import System.FilePath
 import Data.Maybe
diff --git a/src/Propellor/PropAccum.hs b/src/Propellor/PropAccum.hs
--- a/src/Propellor/PropAccum.hs
+++ b/src/Propellor/PropAccum.hs
@@ -78,9 +78,3 @@
 	-> RevertableProperty (MetaTypes y) (MetaTypes z)
 	-> Props (MetaTypes (Combine x z))
 Props c ! p = Props (c ++ [toChildProperty (revert p)])
-
--- addPropsHost :: Host -> [Prop] -> Host
--- addPropsHost (Host hn ps i) p = Host hn ps' i'
---   where
--- 	ps' = ps ++ [toChildProperty p]
--- 	i' = i <> getInfoRecursive p
diff --git a/src/Propellor/Property/Attic.hs b/src/Propellor/Property/Attic.hs
--- a/src/Propellor/Property/Attic.hs
+++ b/src/Propellor/Property/Attic.hs
@@ -1,4 +1,6 @@
 -- | Maintainer: Félix Sipma <felix+propellor@gueux.org>
+--
+-- Support for the Attic backup tool <https://attic-backup.org/>
 
 module Propellor.Property.Attic
 	( installed
diff --git a/src/Propellor/Property/Borg.hs b/src/Propellor/Property/Borg.hs
new file mode 100644
--- /dev/null
+++ b/src/Propellor/Property/Borg.hs
@@ -0,0 +1,155 @@
+-- | Maintainer: Félix Sipma <felix+propellor@gueux.org>
+--
+-- Support for the Borg backup tool <https://github.com/borgbackup>
+
+module Propellor.Property.Borg
+	( installed
+	, repoExists
+	, init
+	, restored
+	, backup
+	, KeepPolicy (..)
+	) where
+
+import Propellor.Base hiding (init)
+import Prelude hiding (init)
+import qualified Propellor.Property.Apt as Apt
+import qualified Propellor.Property.Cron as Cron
+import Data.List (intercalate)
+
+type BorgParam = String
+
+type BorgRepo = FilePath
+
+installed :: Property DebianLike
+installed = withOS desc $ \w o -> case o of
+	(Just (System (Debian (Stable "jessie")) _)) -> ensureProperty w $
+		Apt.installedBackport ["borgbackup"]
+	_ -> ensureProperty w $
+		Apt.installed ["borgbackup"]
+  where
+        desc = "installed borgbackup"
+
+repoExists :: BorgRepo -> IO Bool
+repoExists repo = boolSystem "borg" [Param "list", File repo]
+
+-- | Inits a new borg repository
+init :: BorgRepo -> Property DebianLike
+init backupdir = check (not <$> repoExists backupdir) (cmdProperty "borg" initargs)
+	`requires` installed
+  where
+	initargs =
+		[ "init"
+		, backupdir
+		]
+
+-- | Restores a directory from an borg backup.
+--
+-- Only does anything if the directory does not exist, or exists,
+-- but is completely empty.
+--
+-- The restore is performed atomically; restoring to a temp directory
+-- and then moving it to the directory.
+restored :: FilePath -> BorgRepo -> Property DebianLike
+restored dir backupdir = go `requires` installed
+  where
+	go :: Property DebianLike
+	go = property (dir ++ " restored by borg") $ ifM (liftIO needsRestore)
+		( do
+			warningMessage $ dir ++ " is empty/missing; restoring from backup ..."
+			liftIO restore
+		, noChange
+		)
+
+	needsRestore = null <$> catchDefaultIO [] (dirContents dir)
+
+	restore = withTmpDirIn (takeDirectory dir) "borg-restore" $ \tmpdir -> do
+		ok <- boolSystem "borg" $
+			[ Param "extract"
+			, Param backupdir
+			, Param tmpdir
+			]
+		let restoreddir = tmpdir ++ "/" ++ dir
+		ifM (pure ok <&&> doesDirectoryExist restoreddir)
+			( do
+				void $ tryIO $ removeDirectory dir
+				renameDirectory restoreddir dir
+				return MadeChange
+			, return FailedChange
+			)
+
+-- | Installs a cron job that causes a given directory to be backed
+-- up, by running borg with some parameters.
+--
+-- If the directory does not exist, or exists but is completely empty,
+-- this Property will immediately restore it from an existing backup.
+--
+-- So, this property can be used to deploy a directory of content
+-- to a host, while also ensuring any changes made to it get backed up.
+-- For example:
+--
+-- >	& Borg.backup "/srv/git" "root@myserver:/mnt/backup/git.borg" Cron.Daily
+-- >		["--exclude=/srv/git/tobeignored"]
+-- >		[Borg.KeepDays 7, Borg.KeepWeeks 4, Borg.KeepMonths 6, Borg.KeepYears 1]
+--
+-- Note that this property does not make borg encrypt the backup
+-- repository.
+--
+-- Since borg uses a fair amount of system resources, only one borg
+-- backup job will be run at a time. Other jobs will wait their turns to
+-- run.
+backup :: FilePath -> BorgRepo -> Cron.Times -> [BorgParam] -> [KeepPolicy] -> Property DebianLike
+backup dir backupdir crontimes extraargs kp = backup' dir backupdir crontimes extraargs kp
+	`requires` restored dir backupdir
+
+-- | Does a backup, but does not automatically restore.
+backup' :: FilePath -> BorgRepo -> Cron.Times -> [BorgParam] -> [KeepPolicy] -> Property DebianLike
+backup' dir backupdir crontimes extraargs kp = cronjob
+	`describe` desc
+	`requires` installed
+  where
+	desc = backupdir ++ " borg backup"
+	cronjob = Cron.niceJob ("borg_backup" ++ dir) crontimes (User "root") "/" $
+		"flock " ++ shellEscape lockfile ++ " sh -c " ++ backupcmd
+	lockfile = "/var/lock/propellor-borg.lock"
+	backupcmd = intercalate ";" $
+		createCommand
+		: if null kp then [] else [pruneCommand]
+	createCommand = unwords $
+		[ "borg"
+		, "create"
+		, "--stats"
+		]
+		++ map shellEscape extraargs ++
+		[ shellEscape backupdir ++ "::" ++ "$(date --iso-8601=ns --utc)"
+		, shellEscape dir
+		]
+	pruneCommand = unwords $
+		[ "borg"
+		, "prune"
+		, shellEscape backupdir
+		]
+		++
+		map keepParam kp
+
+-- | Constructs an BorgParam that specifies which old backup generations to
+-- keep. By default, all generations are kept. However, when this parameter is
+-- passed to the `backup` property, they will run borg prune to clean out
+-- generations not specified here.
+keepParam :: KeepPolicy -> BorgParam
+keepParam (KeepHours n) = "--keep-hourly=" ++ show n
+keepParam (KeepDays n) = "--keep-daily=" ++ show n
+keepParam (KeepWeeks n) = "--keep-daily=" ++ show n
+keepParam (KeepMonths n) = "--keep-monthly=" ++ show n
+keepParam (KeepYears n) = "--keep-yearly=" ++ show n
+
+-- | Policy for backup generations to keep. For example, KeepDays 30 will
+-- keep the latest backup for each day when a backup was made, and keep the
+-- last 30 such backups. When multiple KeepPolicies are combined together,
+-- backups meeting any policy are kept. See borg's man page for details.
+data KeepPolicy
+	= KeepHours Int
+	| KeepDays Int
+	| KeepWeeks Int
+	| KeepMonths Int
+	| KeepYears Int
diff --git a/src/Propellor/Property/LetsEncrypt.hs b/src/Propellor/Property/LetsEncrypt.hs
--- a/src/Propellor/Property/LetsEncrypt.hs
+++ b/src/Propellor/Property/LetsEncrypt.hs
@@ -1,4 +1,5 @@
--- | This module uses the letsencrypt reference client.
+-- | This module gets LetsEncrypt <https://letsencrypt.org/> certificates 
+-- using CertBot <https://certbot.eff.org/>
 
 module Propellor.Property.LetsEncrypt where
 
@@ -7,6 +8,8 @@
 
 import System.Posix.Files
 
+-- Not using the certbot name yet, until it reaches jessie-backports and
+-- testing.
 installed :: Property DebianLike
 installed = Apt.installed ["letsencrypt"]
 
@@ -74,6 +77,7 @@
 		, "--webroot"
 		, "--webroot-path", webroot
 		, "--text"
+		, "--noninteractive"
 		, "--keep-until-expiring"
 		] ++ map (\d -> "--domain="++d) alldomains
 
diff --git a/src/Propellor/Property/Obnam.hs b/src/Propellor/Property/Obnam.hs
--- a/src/Propellor/Property/Obnam.hs
+++ b/src/Propellor/Property/Obnam.hs
@@ -1,3 +1,5 @@
+-- | Support for the Obnam backup tool <http://obnam.org/>
+
 module Propellor.Property.Obnam where
 
 import Propellor.Base
diff --git a/src/Propellor/Property/SiteSpecific/GitAnnexBuilder.hs b/src/Propellor/Property/SiteSpecific/GitAnnexBuilder.hs
--- a/src/Propellor/Property/SiteSpecific/GitAnnexBuilder.hs
+++ b/src/Propellor/Property/SiteSpecific/GitAnnexBuilder.hs
@@ -135,6 +135,8 @@
 		& User.accountFor (User builduser)
 		& tree arch flavor
 		& stackInstalled
+		-- Workaround https://github.com/commercialhaskell/stack/issues/2093
+		& Apt.installed ["libtinfo-dev"]
 
 stackInstalled :: Property Linux
 stackInstalled = withOS "stack installed" $ \w o ->
diff --git a/src/Propellor/Types/ZFS.hs b/src/Propellor/Types/ZFS.hs
--- a/src/Propellor/Types/ZFS.hs
+++ b/src/Propellor/Types/ZFS.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE ConstrainedClassMethods #-}
 -- | Types for ZFS Properties.
 --
 -- Copyright 2016 Evan Cofsky <evan@theunixman.com>
diff --git a/src/Utility/Directory.hs b/src/Utility/Directory.hs
--- a/src/Utility/Directory.hs
+++ b/src/Utility/Directory.hs
@@ -6,15 +6,14 @@
  -}
 
 {-# LANGUAGE CPP #-}
-{-# OPTIONS_GHC -fno-warn-tabs -w #-}
+{-# OPTIONS_GHC -fno-warn-tabs #-}
 
 module Utility.Directory (
 	module Utility.Directory,
-	module System.Directory
+	module Utility.SystemDirectory
 ) where
 
 import System.IO.Error
-import System.Directory hiding (isSymbolicLink)
 import Control.Monad
 import System.FilePath
 import Control.Applicative
@@ -31,6 +30,7 @@
 import Control.Monad.IfElse
 #endif
 
+import Utility.SystemDirectory
 import Utility.PosixFiles
 import Utility.Tmp
 import Utility.Exception
diff --git a/src/Utility/Exception.hs b/src/Utility/Exception.hs
--- a/src/Utility/Exception.hs
+++ b/src/Utility/Exception.hs
@@ -21,7 +21,8 @@
 	tryNonAsync,
 	tryWhenExists,
 	catchIOErrorType,
-	IOErrorType(..)
+	IOErrorType(..),
+	catchPermissionDenied,
 ) where
 
 import Control.Monad.Catch as X hiding (Handler)
@@ -97,3 +98,6 @@
 	onlymatching e
 		| ioeGetErrorType e == errtype = onmatchingerr e
 		| otherwise = throwM e
+
+catchPermissionDenied :: MonadCatch m => (IOException -> m a) -> m a -> m a
+catchPermissionDenied = catchIOErrorType PermissionDenied
diff --git a/src/Utility/FileMode.hs b/src/Utility/FileMode.hs
--- a/src/Utility/FileMode.hs
+++ b/src/Utility/FileMode.hs
@@ -18,9 +18,10 @@
 import Utility.PosixFiles
 #ifndef mingw32_HOST_OS
 import System.Posix.Files
+import Control.Monad.IO.Class (liftIO)
 #endif
+import Control.Monad.IO.Class (MonadIO)
 import Foreign (complement)
-import Control.Monad.IO.Class (liftIO, MonadIO)
 import Control.Monad.Catch
 
 import Utility.Exception
diff --git a/src/Utility/FileSystemEncoding.hs b/src/Utility/FileSystemEncoding.hs
--- a/src/Utility/FileSystemEncoding.hs
+++ b/src/Utility/FileSystemEncoding.hs
@@ -19,6 +19,7 @@
 	encodeW8NUL,
 	decodeW8NUL,
 	truncateFilePath,
+	setConsoleEncoding,
 ) where
 
 import qualified GHC.Foreign as GHC
@@ -164,3 +165,10 @@
 					else go (c:coll) (cnt - x') (L8.drop 1 bs)
 			_ -> coll
 #endif
+
+{- This avoids ghc's output layer crashing on invalid encoded characters in
+ - filenames when printing them out. -}
+setConsoleEncoding :: IO ()
+setConsoleEncoding = do
+	fileEncoding stdout
+	fileEncoding stderr
diff --git a/src/Utility/PosixFiles.hs b/src/Utility/PosixFiles.hs
--- a/src/Utility/PosixFiles.hs
+++ b/src/Utility/PosixFiles.hs
@@ -1,6 +1,6 @@
 {- POSIX files (and compatablity wrappers).
  -
- - This is like System.PosixCompat.Files, except with a fixed rename.
+ - This is like System.PosixCompat.Files, but with a few fixes.
  -
  - Copyright 2014 Joey Hess <id@joeyh.name>
  -
@@ -21,6 +21,7 @@
 import System.Posix.Files (rename)
 #else
 import qualified System.Win32.File as Win32
+import qualified System.Win32.HardLink as Win32
 #endif
 
 {- System.PosixCompat.Files.rename on Windows calls renameFile,
@@ -31,4 +32,11 @@
 #ifdef mingw32_HOST_OS
 rename :: FilePath -> FilePath -> IO ()
 rename src dest = Win32.moveFileEx src dest Win32.mOVEFILE_REPLACE_EXISTING
+#endif
+
+{- System.PosixCompat.Files.createLink throws an error, but windows
+ - does support hard links. -}
+#ifdef mingw32_HOST_OS
+createLink :: FilePath -> FilePath -> IO ()
+createLink = Win32.createHardLink
 #endif
diff --git a/src/Utility/SystemDirectory.hs b/src/Utility/SystemDirectory.hs
new file mode 100644
--- /dev/null
+++ b/src/Utility/SystemDirectory.hs
@@ -0,0 +1,16 @@
+{- System.Directory without its conflicting isSymbolicLink
+ -
+ - Copyright 2016 Joey Hess <id@joeyh.name>
+ -
+ - License: BSD-2-clause
+ -}
+
+-- Disable warnings because only some versions of System.Directory export
+-- isSymbolicLink.
+{-# OPTIONS_GHC -fno-warn-tabs -w #-}
+
+module Utility.SystemDirectory (
+	module System.Directory
+) where
+
+import System.Directory hiding (isSymbolicLink)
diff --git a/src/Utility/Tmp.hs b/src/Utility/Tmp.hs
--- a/src/Utility/Tmp.hs
+++ b/src/Utility/Tmp.hs
@@ -11,9 +11,9 @@
 module Utility.Tmp where
 
 import System.IO
-import System.Directory
 import Control.Monad.IfElse
 import System.FilePath
+import System.Directory
 import Control.Monad.IO.Class
 #ifndef mingw32_HOST_OS
 import System.Posix.Temp (mkdtemp)
diff --git a/src/Utility/UserInfo.hs b/src/Utility/UserInfo.hs
--- a/src/Utility/UserInfo.hs
+++ b/src/Utility/UserInfo.hs
@@ -17,9 +17,7 @@
 import Utility.Env
 
 import System.PosixCompat
-#ifndef mingw32_HOST_OS
 import Control.Applicative
-#endif
 import Prelude
 
 {- Current user's home directory.
@@ -58,6 +56,6 @@
 #ifndef mingw32_HOST_OS
 	go [] = extract <$> (getUserEntryForID =<< getEffectiveUserID)
 #else
-	go [] = error $ "environment not set: " ++ show envvars
+	go [] = extract <$> error ("environment not set: " ++ show envvars)
 #endif
 	go (v:vs) = maybe (go vs) return =<< getEnv v
