diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -1,6 +1,8 @@
 # Calculator
 
-A calculator repl.
+[![Build Status](https://travis-ci.org/sumitsahrawat/calculator.svg)](https://travis-ci.org/sumitsahrawat/calculator)
+
+A feature rich calculator repl.
 
 ## Features
 
diff --git a/calculator.cabal b/calculator.cabal
--- a/calculator.cabal
+++ b/calculator.cabal
@@ -1,5 +1,5 @@
 name:                calculator
-version:             0.4.1.1
+version:             0.4.1.2
 synopsis:            A calculator repl, with variables, functions & Mathematica like dynamic plots.
 description:         A calculator repl that processes mathematical expressions.
                      Does basic arithmetic, and provides pre-defined basic mathematical functions.
@@ -37,7 +37,7 @@
                      , Calculator.Prim.Result
                      , Calculator.Color
   -- other-extensions:    
-  build-depends:       base >=4.7 && <4.9
+  build-depends:       base >=4.6 && <5.0
                      , containers
                      , haskeline
                      , parsec
diff --git a/stack.yaml b/stack.yaml
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,42 +1,66 @@
-# For more information, see: https://github.com/commercialhaskell/stack/blob/master/doc/yaml_configuration.md
+# This file was automatically generated by 'stack init'
+# 
+# Some commonly used options have been documented as comments in this file.
+# For advanced use and comprehensive documentation of the format, please see:
+# http://docs.haskellstack.org/en/stable/yaml_configuration/
 
-# Specifies the GHC version and set of packages available (e.g., lts-3.5, nightly-2015-09-21, ghc-7.10.2)
-resolver: ghc-7.10.1
+# Resolver to choose a 'specific' stackage snapshot or a compiler version.
+# A snapshot resolver dictates the compiler version and the set of packages
+# to be used for project dependencies. For example:
+# 
+# resolver: lts-3.5
+# resolver: nightly-2015-09-21
+# resolver: ghc-7.10.2
+# resolver: ghcjs-0.1.0_ghc-7.10.2
+# resolver:
+#  name: custom-snapshot
+#  location: "./custom-snapshot.yaml"
+resolver: lts-7.3
 
-# Local packages, usually specified by relative directory name
+# User packages to be built.
+# Various formats can be used as shown in the example below.
+# 
+# packages:
+# - some-directory
+# - https://example.com/foo/bar/baz-0.0.2.tar.gz
+# - location:
+#    git: https://github.com/commercialhaskell/stack.git
+#    commit: e7b331f14bcffb8367cd58fbfc8b40ec7642100a
+# - location: https://github.com/commercialhaskell/stack/commit/e7b331f14bcffb8367cd58fbfc8b40ec7642100a
+#   extra-dep: true
+#  subdirs:
+#  - auto-update
+#  - wai
+# 
+# A package marked 'extra-dep: true' will only be built if demanded by a
+# non-dependency (i.e. a user package), and its test suites and benchmarks
+# will not be run. This is useful for tweaking upstream packages.
 packages:
 - '.'
-
-# Packages to be pulled from upstream that are not in the resolver (e.g., acme-missiles-0.3)
-extra-deps:
-- QuickCheck-2.8.1
-- cairo-0.13.1.0
-- colour-2.3.3
-- fixed-vector-0.8.1.0
-- gio-0.13.1.0
-- glib-0.13.2.1
-- gtk-0.13.9
-- hmatrix-0.16.1.5
-- pango-0.13.1.0
-- plot-0.2.3.4
-- plot-gtk-ui-0.3.0.0
-- storable-complex-0.2.2
-- tf-random-0.5
+# Dependency packages to be pulled from upstream that are not in the resolver
+# (e.g., acme-missiles-0.3)
+extra-deps: []
 
 # Override default flag values for local packages and extra-deps
 flags: {}
 
+# Extra package databases containing global packages
+extra-package-dbs: []
+
 # Control whether we use the GHC we find on the path
 # system-ghc: true
-
+# 
 # Require a specific version of stack, using version ranges
 # require-stack-version: -any # Default
-# require-stack-version: >= 0.1.4.0
-
+# require-stack-version: ">=1.1"
+# 
 # Override the architecture used by stack, especially useful on Windows
 # arch: i386
 # arch: x86_64
-
+# 
 # Extra directories used by stack for building
 # extra-include-dirs: [/path/to/dir]
 # extra-lib-dirs: [/path/to/dir]
+# 
+# Allow a newer minor version of GHC than the snapshot specifies
+# compiler-check: newer-minor