diff --git a/Octokit.Tests.Integration/Clients/SearchClientTests.cs b/Octokit.Tests.Integration/Clients/SearchClientTests.cs
index 616b04ae..9d1e90d1 100644
--- a/Octokit.Tests.Integration/Clients/SearchClientTests.cs
+++ b/Octokit.Tests.Integration/Clients/SearchClientTests.cs
@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
 using Octokit;
@@ -23,6 +24,18 @@ public class SearchClientTests
         Assert.NotEmpty(repos.Items);
     }
 
+    [IntegrationTest]
+    public async Task SearchForCSharpRepositoriesUpdatedIn2020()
+    {
+        var request = new SearchRepositoriesRequest("csharp")
+        {
+            Updated = DateRange.GreaterThan(new DateTimeOffset(2020, 1, 1, 0, 0, 0, TimeSpan.Zero))
+        };
+        var repos = await _gitHubClient.Search.SearchRepo(request);
+
+        Assert.NotEmpty(repos.Items);
+    }
+
     [IntegrationTest]
     public async Task SearchForForkedRepositories()
     {
diff --git a/Octokit.Tests/Clients/SearchClientTests.cs b/Octokit.Tests/Clients/SearchClientTests.cs
index c2ebdabf..fc6eafe1 100644
--- a/Octokit.Tests/Clients/SearchClientTests.cs
+++ b/Octokit.Tests/Clients/SearchClientTests.cs
@@ -219,7 +219,7 @@ namespace Octokit.Tests.Clients
                 client.SearchUsers(request);
                 connection.Received().Get<SearchUsersResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/users"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+created:>2014-01-01T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+created:>2014-01-01T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -232,7 +232,7 @@ namespace Octokit.Tests.Clients
                 client.SearchUsers(request);
                 connection.Received().Get<SearchUsersResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/users"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+created:>=2014-01-01T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+created:>=2014-01-01T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -245,7 +245,7 @@ namespace Octokit.Tests.Clients
                 client.SearchUsers(request);
                 connection.Received().Get<SearchUsersResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/users"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+created:<=2014-01-01T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+created:<=2014-01-01T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -258,7 +258,7 @@ namespace Octokit.Tests.Clients
                 client.SearchUsers(request);
                 connection.Received().Get<SearchUsersResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/users"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+created:<2014-01-01T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+created:<2014-01-01T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -275,7 +275,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchUsersResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/users"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+created:2014-01-01T00:00:00+00:00..2014-02-01T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+created:2014-01-01T00:00:00%2B00:00..2014-02-01T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -532,7 +532,7 @@ namespace Octokit.Tests.Clients
                 request.Created = DateRange.GreaterThan(new DateTimeOffset(new DateTime(2011, 1, 1), TimeSpan.Zero));
                 client.SearchRepo(request);
                 connection.Received().Get<SearchRepositoryResult>(Arg.Is<Uri>(u => u.ToString() == "search/repositories"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+created:>2011-01-01T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+created:>2011-01-01T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -545,7 +545,7 @@ namespace Octokit.Tests.Clients
                 request.Created = DateRange.GreaterThanOrEquals(new DateTimeOffset(new DateTime(2011, 1, 1), TimeSpan.Zero));
                 client.SearchRepo(request);
                 connection.Received().Get<SearchRepositoryResult>(Arg.Is<Uri>(u => u.ToString() == "search/repositories"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+created:>=2011-01-01T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+created:>=2011-01-01T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -558,7 +558,7 @@ namespace Octokit.Tests.Clients
                 request.Created = DateRange.LessThan(new DateTimeOffset(new DateTime(2011, 1, 1), TimeSpan.Zero));
                 client.SearchRepo(request);
                 connection.Received().Get<SearchRepositoryResult>(Arg.Is<Uri>(u => u.ToString() == "search/repositories"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+created:<2011-01-01T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+created:<2011-01-01T00:00:00%2B00:00"));
             }
 
 
@@ -572,7 +572,7 @@ namespace Octokit.Tests.Clients
                 request.Created = DateRange.LessThanOrEquals(new DateTimeOffset(new DateTime(2011, 1, 1), TimeSpan.Zero));
                 client.SearchRepo(request);
                 connection.Received().Get<SearchRepositoryResult>(Arg.Is<Uri>(u => u.ToString() == "search/repositories"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+created:<=2011-01-01T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+created:<=2011-01-01T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -588,7 +588,7 @@ namespace Octokit.Tests.Clients
                 client.SearchRepo(request);
 
                 connection.Received().Get<SearchRepositoryResult>(Arg.Is<Uri>(u => u.ToString() == "search/repositories"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+created:2011-01-01T00:00:00+00:00..2012-11-11T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+created:2011-01-01T00:00:00%2B00:00..2012-11-11T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -601,7 +601,7 @@ namespace Octokit.Tests.Clients
                 request.Updated = DateRange.GreaterThan(new DateTimeOffset(new DateTime(2013, 1, 1), TimeSpan.Zero));
                 client.SearchRepo(request);
                 connection.Received().Get<SearchRepositoryResult>(Arg.Is<Uri>(u => u.ToString() == "search/repositories"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+pushed:>2013-01-01T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+pushed:>2013-01-01T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -614,7 +614,7 @@ namespace Octokit.Tests.Clients
                 request.Updated = DateRange.GreaterThanOrEquals(new DateTimeOffset(new DateTime(2013, 1, 1), TimeSpan.Zero));
                 client.SearchRepo(request);
                 connection.Received().Get<SearchRepositoryResult>(Arg.Is<Uri>(u => u.ToString() == "search/repositories"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+pushed:>=2013-01-01T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+pushed:>=2013-01-01T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -627,7 +627,7 @@ namespace Octokit.Tests.Clients
                 request.Updated = DateRange.LessThan(new DateTimeOffset(new DateTime(2013, 1, 1), TimeSpan.Zero));
                 client.SearchRepo(request);
                 connection.Received().Get<SearchRepositoryResult>(Arg.Is<Uri>(u => u.ToString() == "search/repositories"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+pushed:<2013-01-01T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+pushed:<2013-01-01T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -640,7 +640,7 @@ namespace Octokit.Tests.Clients
                 request.Updated = DateRange.LessThanOrEquals(new DateTimeOffset(new DateTime(2013, 1, 1), TimeSpan.Zero));
                 client.SearchRepo(request);
                 connection.Received().Get<SearchRepositoryResult>(Arg.Is<Uri>(u => u.ToString() == "search/repositories"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+pushed:<=2013-01-01T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+pushed:<=2013-01-01T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -656,7 +656,7 @@ namespace Octokit.Tests.Clients
                 client.SearchRepo(request);
 
                 connection.Received().Get<SearchRepositoryResult>(Arg.Is<Uri>(u => u.ToString() == "search/repositories"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+pushed:2012-04-30T00:00:00+00:00..2012-07-04T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "github+pushed:2012-04-30T00:00:00%2B00:00..2012-07-04T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -1007,7 +1007,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+created:>2014-01-01T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+created:>2014-01-01T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -1022,7 +1022,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+created:>=2014-01-01T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+created:>=2014-01-01T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -1037,7 +1037,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+created:<2014-01-01T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+created:<2014-01-01T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -1052,7 +1052,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+created:<=2014-01-01T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+created:<=2014-01-01T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -1069,7 +1069,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+created:2014-01-01T00:00:00+00:00..2014-02-02T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+created:2014-01-01T00:00:00%2B00:00..2014-02-02T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -1084,7 +1084,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+merged:>2014-01-01T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+merged:>2014-01-01T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -1099,7 +1099,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+merged:>=2014-01-01T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+merged:>=2014-01-01T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -1114,7 +1114,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+merged:<2014-01-01T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+merged:<2014-01-01T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -1129,7 +1129,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+merged:<=2014-01-01T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+merged:<=2014-01-01T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -1146,7 +1146,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+merged:2014-01-01T00:00:00+00:00..2014-02-02T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+merged:2014-01-01T00:00:00%2B00:00..2014-02-02T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -1161,7 +1161,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+updated:>2014-01-01T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+updated:>2014-01-01T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -1176,7 +1176,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+updated:>=2014-01-01T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+updated:>=2014-01-01T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -1191,7 +1191,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+updated:<2014-01-01T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+updated:<2014-01-01T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -1206,7 +1206,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+updated:<=2014-01-01T00:00:00+00:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+updated:<=2014-01-01T00:00:00%2B00:00"));
             }
 
             [Fact]
@@ -1221,7 +1221,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+created:>2014-01-01T02:04:06+10:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+created:>2014-01-01T02:04:06%2B10:00"));
             }
 
             [Fact]
@@ -1236,7 +1236,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+created:>=2014-01-01T02:04:06+10:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+created:>=2014-01-01T02:04:06%2B10:00"));
             }
 
             [Fact]
@@ -1250,7 +1250,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+created:<2014-01-01T02:04:06+10:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+created:<2014-01-01T02:04:06%2B10:00"));
             }
 
             [Fact]
@@ -1265,7 +1265,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+created:<=2014-01-01T02:04:06+10:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+created:<=2014-01-01T02:04:06%2B10:00"));
             }
 
             [Fact]
@@ -1282,7 +1282,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+created:2014-01-01T02:04:06+10:00..2014-02-02T02:04:06+10:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+created:2014-01-01T02:04:06%2B10:00..2014-02-02T02:04:06%2B10:00"));
             }
 
             [Fact]
@@ -1297,7 +1297,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+merged:>2014-01-01T02:04:06+10:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+merged:>2014-01-01T02:04:06%2B10:00"));
             }
 
             [Fact]
@@ -1312,7 +1312,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+merged:>=2014-01-01T02:04:06+10:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+merged:>=2014-01-01T02:04:06%2B10:00"));
             }
 
             [Fact]
@@ -1327,7 +1327,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+merged:<2014-01-01T02:04:06+10:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+merged:<2014-01-01T02:04:06%2B10:00"));
             }
 
             [Fact]
@@ -1342,7 +1342,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+merged:<=2014-01-01T02:04:06+10:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+merged:<=2014-01-01T02:04:06%2B10:00"));
             }
 
             [Fact]
@@ -1359,7 +1359,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+merged:2014-01-01T02:04:06+10:00..2014-02-02T02:04:06+10:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+merged:2014-01-01T02:04:06%2B10:00..2014-02-02T02:04:06%2B10:00"));
             }
 
             [Fact]
@@ -1374,7 +1374,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+updated:>2014-01-01T02:04:06+10:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+updated:>2014-01-01T02:04:06%2B10:00"));
             }
 
             [Fact]
@@ -1389,7 +1389,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+updated:>=2014-01-01T02:04:06+10:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+updated:>=2014-01-01T02:04:06%2B10:00"));
             }
 
             [Fact]
@@ -1404,7 +1404,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+updated:<2014-01-01T02:04:06+10:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+updated:<2014-01-01T02:04:06%2B10:00"));
             }
 
             [Fact]
@@ -1419,7 +1419,7 @@ namespace Octokit.Tests.Clients
 
                 connection.Received().Get<SearchIssuesResult>(
                     Arg.Is<Uri>(u => u.ToString() == "search/issues"),
-                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+updated:<=2014-01-01T02:04:06+10:00"));
+                    Arg.Is<Dictionary<string, string>>(d => d["q"] == "something+updated:<=2014-01-01T02:04:06%2B10:00"));
             }
 
             [Fact]
diff --git a/Octokit/Models/Request/SearchRepositoriesRequest.cs b/Octokit/Models/Request/SearchRepositoriesRequest.cs
index 48d09645..f674fa91 100644
--- a/Octokit/Models/Request/SearchRepositoriesRequest.cs
+++ b/Octokit/Models/Request/SearchRepositoriesRequest.cs
@@ -341,7 +341,7 @@ namespace Octokit
         /// </summary>
         public DateRange(DateTimeOffset from, DateTimeOffset to)
         {
-            query = $"{from.ToString(DateTimePattern, CultureInfo.InvariantCulture)}..{to.ToString(DateTimePattern, CultureInfo.InvariantCulture)}";
+            query = EncodeOffset($"{from.ToString(DateTimePattern, CultureInfo.InvariantCulture)}..{to.ToString(DateTimePattern, CultureInfo.InvariantCulture)}");
         }
 
         /// <summary>
@@ -353,20 +353,25 @@ namespace Octokit
             switch (op)
             {
                 case SearchQualifierOperator.GreaterThan:
-                    query = dateTime.ToString($">{DateTimePattern}", CultureInfo.InvariantCulture);
+                    query = EncodeOffset(dateTime.ToString($">{DateTimePattern}", CultureInfo.InvariantCulture));
                     break;
                 case SearchQualifierOperator.LessThan:
-                    query = dateTime.ToString($"<{DateTimePattern}", CultureInfo.InvariantCulture);
+                    query = EncodeOffset(dateTime.ToString($"<{DateTimePattern}", CultureInfo.InvariantCulture));
                     break;
                 case SearchQualifierOperator.LessThanOrEqualTo:
-                    query = dateTime.ToString($"<={DateTimePattern}", CultureInfo.InvariantCulture);
+                    query = EncodeOffset(dateTime.ToString($"<={DateTimePattern}", CultureInfo.InvariantCulture));
                     break;
                 case SearchQualifierOperator.GreaterThanOrEqualTo:
-                    query = dateTime.ToString($">={DateTimePattern}", CultureInfo.InvariantCulture);
+                    query = EncodeOffset(dateTime.ToString($">={DateTimePattern}", CultureInfo.InvariantCulture));
                     break;
             }
         }
 
+        private string EncodeOffset(string dateTimeOffset)
+        {
+            return dateTimeOffset.Replace("+", "%2B");
+        }
+
         internal string DebuggerDisplay
         {
             get { return string.Format(CultureInfo.InvariantCulture, "Query: {0}", query); }