diff --git a/REQUIRE b/REQUIRE
index b8a5d67..a9ddc7e 100644
--- a/REQUIRE
+++ b/REQUIRE
@@ -1,2 +1,2 @@
 julia 0.4
-Compat 0.4.0
+Compat 0.9.1
diff --git a/src/check_derivative.jl b/src/check_derivative.jl
index a3a47ed..e837655 100644
--- a/src/check_derivative.jl
+++ b/src/check_derivative.jl
@@ -1,19 +1,19 @@
-function check_derivative(f::Function, g::Function, x::Number)
-	auto_g = derivative(f)
-	return maximum(abs(g(x) - auto_g(x)))
-end
-
-function check_gradient{T <: Number}(f::Function, g::Function, x::Vector{T})
-	auto_g = gradient(f)
-	return maximum(abs(g(x) - auto_g(x)))
-end
-
-function check_second_derivative(f::Function, h::Function, x::Number)
-	auto_h = second_derivative(f)
-	return maximum(abs(h(x) - auto_h(x)))
-end
-
-function check_hessian{T <: Number}(f::Function, h::Function, x::Vector{T})
-	auto_h = hessian(f)
-	return maximum(abs(h(x) - auto_h(x)))
-end
+Compat.@compat function check_derivative(f::Function, g::Function, x::Number)
+    auto_g = derivative(f)
+    return maximum(abs.(g(x) - auto_g(x)))
+end
+
+Compat.@compat function check_gradient{T <: Number}(f::Function, g::Function, x::Vector{T})
+    auto_g = gradient(f)
+    return maximum(abs.(g(x) - auto_g(x)))
+end
+
+Compat.@compat function check_second_derivative(f::Function, h::Function, x::Number)
+    auto_h = second_derivative(f)
+    return maximum(abs.(h(x) - auto_h(x)))
+end
+
+Compat.@compat function check_hessian{T <: Number}(f::Function, h::Function, x::Vector{T})
+    auto_h = hessian(f)
+    return maximum(abs.(h(x) - auto_h(x)))
+end