diff --git a/.travis.yml b/.travis.yml
index eb9f3fc..c405aac 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,7 +4,6 @@ os:
   - linux
   - osx
 julia:
-  - 0.5
   - 0.6
   - nightly
 notifications:
diff --git a/REQUIRE b/REQUIRE
index 3213e5a..26ce689 100644
--- a/REQUIRE
+++ b/REQUIRE
@@ -1,3 +1,2 @@
-julia 0.5
-Compat 0.17.0
+julia 0.6
 QuadGK 0.1.1
diff --git a/appveyor.yml b/appveyor.yml
index 0dd2e73..f4727cb 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -1,7 +1,5 @@
 environment:
   matrix:
-  - JULIA_URL: "https://julialang-s3.julialang.org/bin/winnt/x86/0.5/julia-0.5-latest-win32.exe"
-  - JULIA_URL: "https://julialang-s3.julialang.org/bin/winnt/x64/0.5/julia-0.5-latest-win64.exe"
   - JULIA_URL: "https://julialang-s3.julialang.org/bin/winnt/x86/0.6/julia-0.6-latest-win32.exe"
   - JULIA_URL: "https://julialang-s3.julialang.org/bin/winnt/x64/0.6/julia-0.6-latest-win64.exe"
   - JULIA_URL: "https://julialangnightlies-s3.julialang.org/bin/winnt/x86/julia-latest-win32.exe"
diff --git a/src/Cosmology.jl b/src/Cosmology.jl
index 393402a..9dc2e92 100644
--- a/src/Cosmology.jl
+++ b/src/Cosmology.jl
@@ -1,6 +1,5 @@
 module Cosmology
 
-using Compat
 using QuadGK
 
 export cosmology,
@@ -17,12 +16,12 @@ export cosmology,
        lookback_time_gyr,
        scale_factor
 
-@compat abstract type AbstractCosmology end
-@compat abstract type AbstractClosedCosmology <: AbstractCosmology end
-@compat abstract type AbstractFlatCosmology <: AbstractCosmology end
-@compat abstract type AbstractOpenCosmology <: AbstractCosmology end
+abstract type AbstractCosmology end
+abstract type AbstractClosedCosmology <: AbstractCosmology end
+abstract type AbstractFlatCosmology <: AbstractCosmology end
+abstract type AbstractOpenCosmology <: AbstractCosmology end
 
-immutable FlatLCDM{T<:Real} <: AbstractFlatCosmology
+struct FlatLCDM{T<:Real} <: AbstractFlatCosmology
     h::T
     Ω_Λ::T
     Ω_m::T
@@ -34,7 +33,7 @@ FlatLCDM(h::Real, Ω_Λ::Real, Ω_m::Real, Ω_r::Real) =
 
 a2E(c::FlatLCDM, a::Float64) = sqrt(c.Ω_r + c.Ω_m*a + c.Ω_Λ*a^4)
 
-immutable ClosedLCDM{T<:Real} <: AbstractClosedCosmology
+struct ClosedLCDM{T<:Real} <: AbstractClosedCosmology
     h::T
     Ω_k::T
     Ω_Λ::T
@@ -46,7 +45,7 @@ ClosedLCDM(h::Real, Ω_k::Real, Ω_Λ::Real, Ω_m::Real, Ω_r::Real) =
                        float(Ω_r))...)
 
 
-immutable OpenLCDM{T<:Real} <: AbstractOpenCosmology
+struct OpenLCDM{T<:Real} <: AbstractOpenCosmology
     h::T
     Ω_k::T
     Ω_Λ::T
@@ -66,7 +65,7 @@ end
 for c in ("Flat", "Open", "Closed")
     name = Symbol("$(c)WCDM")
     @eval begin
-        immutable $(name){T<:Real} <: $(Symbol("Abstract$(c)Cosmology"))
+        struct $(name){T<:Real} <: $(Symbol("Abstract$(c)Cosmology"))
             h::T
             Ω_k::T
             Ω_Λ::T
diff --git a/test/runtests.jl b/test/runtests.jl
index 8f1e878..c73aecf 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -1,4 +1,3 @@
-include("../src/Cosmology.jl")
 using Cosmology
 using Base.Test