diff --git a/Project.toml b/Project.toml
index 1b6c1f7..b3036bb 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,12 +1,12 @@
 name = "PooledArrays"
 uuid = "2dfb63ee-cc39-5dd5-95bd-886bf059d720"
-version = "1.0.0"
+version = "1.1.0"
 
 [deps]
 DataAPI = "9a962f9c-6df0-11e9-0e5d-c546b8b5ee8a"
 
 [compat]
-DataAPI = "1"
+DataAPI = "1.5"
 julia = "1"
 
 [extras]
diff --git a/src/PooledArrays.jl b/src/PooledArrays.jl
index 9479039..fa4b9d0 100644
--- a/src/PooledArrays.jl
+++ b/src/PooledArrays.jl
@@ -118,6 +118,9 @@ The `compress` argument controls whether the default size of 32 bits is used (`U
 unsigned, `Int32` for signed) or if smaller integer types are chosen when they can be used.
 If `array` is not a `PooledArray` then the order of elements in `refpool` in the resulting
 `PooledArray` is the order of first appereance of elements in `array`.
+
+Note that if you hold mutable objects in `PooledArray` it is not allowed to modify them
+after they are stored in it.
 """
 PooledArray
 
@@ -156,6 +159,7 @@ PooledArray(t::Type, r::Type) = PooledArray(Array(t,0), r)
 DataAPI.refarray(pa::PooledArray) = pa.refs
 DataAPI.refvalue(pa::PooledArray, i::Integer) = pa.pool[i]
 DataAPI.refpool(pa::PooledArray) = pa.pool
+DataAPI.invrefpool(pa::PooledArray) = pa.invpool
 
 Base.size(pa::PooledArray) = size(pa.refs)
 Base.length(pa::PooledArray) = length(pa.refs)
diff --git a/test/runtests.jl b/test/runtests.jl
index a503773..60c99b7 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -1,6 +1,6 @@
 using Test
 using PooledArrays
-using DataAPI: refarray, refvalue, refpool
+using DataAPI: refarray, refvalue, refpool, invrefpool
 
 @testset "PooledArrays" begin
     a = rand(10)
@@ -87,7 +87,8 @@ using DataAPI: refarray, refvalue, refpool
         @test refvalue(s, refarray(s)[i]) == s[i]
     end
     @test refpool(s) == ["a", "b"]
-
+    @test invrefpool(s) == Dict("a" => 1, "b" => 2)
+    
     @testset "push!" begin
         xs = PooledArray([10, 20, 30])
         @test xs === push!(xs, -100)