diff --git a/Octokit/Octokit-Mono.csproj b/Octokit/Octokit-Mono.csproj
index 7db1a0af..3c26538d 100644
--- a/Octokit/Octokit-Mono.csproj
+++ b/Octokit/Octokit-Mono.csproj
@@ -26,7 +26,7 @@
     <DebugType>full</DebugType>
     <Optimize>true</Optimize>
     <IntermediateOutputPath>obj\Release\Mono</IntermediateOutputPath>
-    <DefineConstants>TRACE;CODE_ANALYSIS;SIMPLE_JSON_OBJARRAYINTERNAL;SIMPLE_JSON_INTERNAL;NET_45</DefineConstants>
+    <DefineConstants>TRACE;CODE_ANALYSIS;SIMPLE_JSON_OBJARRAYINTERNAL;SIMPLE_JSON_INTERNAL;NET_45;SIMPLE_JSON_READONLY_COLLECTIONS</DefineConstants>
     <OutputPath>bin\Release\Mono</OutputPath>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
diff --git a/Octokit/Octokit-Portable.csproj b/Octokit/Octokit-Portable.csproj
index 0b72c890..72f12cbd 100644
--- a/Octokit/Octokit-Portable.csproj
+++ b/Octokit/Octokit-Portable.csproj
@@ -31,7 +31,7 @@
     <DebugType>pdbonly</DebugType>
     <Optimize>true</Optimize>
     <OutputPath>bin\Release\Portable\</OutputPath>
-    <DefineConstants>TRACE;NETFX_CORE;CODE_ANALYSIS;SIMPLE_JSON_OBJARRAYINTERNAL;SIMPLE_JSON_INTERNAL;NET_45;PORTABLE</DefineConstants>
+    <DefineConstants>TRACE;NETFX_CORE;CODE_ANALYSIS;SIMPLE_JSON_OBJARRAYINTERNAL;SIMPLE_JSON_INTERNAL;NET_45;PORTABLE;SIMPLE_JSON_READONLY_COLLECTIONS</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
     <RunCodeAnalysis>true</RunCodeAnalysis>
diff --git a/Octokit/Octokit-netcore45.csproj b/Octokit/Octokit-netcore45.csproj
index 69754d1d..31cf5cef 100644
--- a/Octokit/Octokit-netcore45.csproj
+++ b/Octokit/Octokit-netcore45.csproj
@@ -35,7 +35,7 @@
     <Optimize>true</Optimize>
     <IntermediateOutputPath>obj\Release\NetCore45</IntermediateOutputPath>
     <OutputPath>bin\Release\NetCore45\</OutputPath>
-    <DefineConstants>TRACE;NETFX_CORE;CODE_ANALYSIS;SIMPLE_JSON_OBJARRAYINTERNAL;SIMPLE_JSON_INTERNAL;NET_45</DefineConstants>
+    <DefineConstants>TRACE;NETFX_CORE;CODE_ANALYSIS;SIMPLE_JSON_OBJARRAYINTERNAL;SIMPLE_JSON_INTERNAL;NET_45;SIMPLE_JSON_READONLY_COLLECTIONS</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
     <RunCodeAnalysis>true</RunCodeAnalysis>