diff --git a/Changelog.md b/Changelog.md
--- a/Changelog.md
+++ b/Changelog.md
@@ -1,6 +1,10 @@
 # Changelog for `proto-lens`
 
-## v0.5.0.0
+## v0.5.0.1
+- Bump the upper bound on `profunctors` to allow 5.4.
+- Bump the upper bound on `primitive` to allow 0.7.
+- Allow text format protobuf strings to contain unescaped quote characters
+  different from the delimiters (#320).
 
 ### Breaking Changes
 - Merge the `lens-labels` library into `proto-lens`:
diff --git a/proto-lens.cabal b/proto-lens.cabal
--- a/proto-lens.cabal
+++ b/proto-lens.cabal
@@ -1,13 +1,11 @@
-cabal-version: 1.12
-
--- This file has been generated from package.yaml by hpack version 0.31.1.
+-- This file has been generated from package.yaml by hpack version 0.28.2.
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: b65e668c793e451c25341ac7d0d137ca534c8388cc6417c3119fc6cb5122e638
+-- hash: 29ea431ef6a13fa63ce37199c52c0b46df4db87cdfa86c0241034a9d9c5aaa12
 
 name:           proto-lens
-version:        0.5.0.0
+version:        0.5.0.1
 synopsis:       A lens-based implementation of protocol buffers in Haskell.
 description:    The proto-lens library provides an API for protocol buffers using modern Haskell language and library patterns.  Specifically, it provides:
                 .
@@ -25,11 +23,12 @@
 license:        BSD3
 license-file:   LICENSE
 build-type:     Simple
+cabal-version:  >= 1.10
 extra-source-files:
     Changelog.md
 data-files:
-    proto-lens-imports/google/protobuf/descriptor.proto
     proto-lens-imports/google/protobuf/compiler/plugin.proto
+    proto-lens-imports/google/protobuf/descriptor.proto
 
 source-repository head
   type: git
@@ -72,8 +71,8 @@
     , lens-family ==1.2.*
     , parsec ==3.1.*
     , pretty ==1.1.*
-    , primitive ==0.6.*
-    , profunctors >=5.2 && <5.4
+    , primitive >=0.6 && <0.8
+    , profunctors >=5.2 && <5.5
     , tagged ==0.8.*
     , text ==1.2.*
     , transformers >=0.4 && <0.6
diff --git a/src/Data/ProtoLens/TextFormat/Parser.hs b/src/Data/ProtoLens/TextFormat/Parser.hs
--- a/src/Data/ProtoLens/TextFormat/Parser.hs
+++ b/src/Data/ProtoLens/TextFormat/Parser.hs
@@ -6,6 +6,8 @@
 
 -- | Helper utilities to parse the human-readable text format into a
 -- proto-agnostic syntax tree.
+{-# LANGUAGE FlexibleContexts #-}
+
 module Data.ProtoLens.TextFormat.Parser
     ( Message
     , Field(..)
@@ -129,14 +131,14 @@
 protoStringLiteral :: Parser ByteString
 protoStringLiteral = do
     initialQuoteChar <- char '\'' <|> char '\"'
-    word8s <- many stringChar
+    word8s <- many $ stringChar initialQuoteChar
     _ <- char initialQuoteChar
     return $ pack word8s
   where
-    stringChar :: Parser Word8
-    stringChar = nonEscape <|> stringEscape
-    nonEscape  = fmap (fromIntegral . ord)
-        $ satisfy (\c -> c `notElem` "\\\'\"" && ord c < 256)
+    stringChar :: Char -> Parser Word8
+    stringChar quote = (nonEscape quote) <|> stringEscape
+    nonEscape quote = fmap (fromIntegral . ord)
+        $ satisfy (\c -> c `notElem` "\\" ++ [quote] && ord c < 256)
     stringEscape = char '\\' >> (octal <|> hex <|> unicode <|> simple)
     octal = do d0 <- octDigit
                d1 <- optionMaybe octDigit