diff --git a/.travis.yml b/.travis.yml
index 956ed21cfc..6962cbaffe 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -16,7 +16,7 @@ matrix:
         - CMAKE_OPTIONS="-DCMAKE_BUILD_TYPE=Debug -DCMAKE_OSX_DEPLOYMENT_TARGET=10.9"
 
     - os: osx
-      osx_image: xcode9.4
+      osx_image: xcode10
       env:
         - CMAKE_OPTIONS="-DCMAKE_BUILD_TYPE=Release -DCMAKE_OSX_DEPLOYMENT_TARGET=10.9"
 
diff --git a/src/p_teleport.cpp b/src/p_teleport.cpp
index 2bb71f82b7..78f21b741f 100644
--- a/src/p_teleport.cpp
+++ b/src/p_teleport.cpp
@@ -523,18 +523,21 @@ bool EV_SilentLineTeleport (line_t *line, int side, AActor *thing, int id, INTBO
 
 			// Is this really still necessary with real math instead of imprecise trig tables?
 #if 1
+			const double fudgeamount = 1. / 65536.;
+
 			int side = reverse || (player && stepdown);
 			int fudge = FUDGEFACTOR;
 
 			double dx = line->Delta().X;
 			double dy = line->Delta().Y;
+
 			// Make sure we are on correct side of exit linedef.
 			while (P_PointOnLineSidePrecise(p, l) != side && --fudge >= 0)
 			{
 				if (fabs(dx) > fabs(dy))
-					p.Y -= (dx < 0) != side ? -1 : 1;
+					p.Y -= (dx < 0) != side ? -fudgeamount : fudgeamount;
 				else
-					p.X += (dy < 0) != side ? -1 : 1;
+					p.X += (dy < 0) != side ? -fudgeamount : fudgeamount;
 			}
 #endif
 
diff --git a/src/r_data/models/models_md3.cpp b/src/r_data/models/models_md3.cpp
index f47ee90cd6..b3f12b853c 100644
--- a/src/r_data/models/models_md3.cpp
+++ b/src/r_data/models/models_md3.cpp
@@ -363,7 +363,10 @@ void FMD3Model::RenderFrame(FModelRenderer *renderer, FTexture * skin, int frame
 				surfaceSkin = TexMan(surf->skins[0]);
 			}
 
-			if (!surfaceSkin) return;
+			if (!surfaceSkin)
+			{
+				continue;
+			}
 		}
 
 		renderer->SetMaterial(surfaceSkin, false, translation);
diff --git a/src/version.h b/src/version.h
index e014d54ed9..61c6ceff8e 100644
--- a/src/version.h
+++ b/src/version.h
@@ -48,16 +48,16 @@ const char *GetVersionString();
 #ifdef GIT_DESCRIPTION
 #define VERSIONSTR GIT_DESCRIPTION
 #else
-#define VERSIONSTR "3.6pre"
+#define VERSIONSTR "3.7pre"
 #endif
 
 // The version as seen in the Windows resource
-#define RC_FILEVERSION 3,5,9999,0
-#define RC_PRODUCTVERSION 3,5,9999,0
+#define RC_FILEVERSION 3,6,9999,0
+#define RC_PRODUCTVERSION 3,6,9999,0
 #define RC_PRODUCTVERSION2 VERSIONSTR
 // These are for content versioning.
 #define VER_MAJOR 3
-#define VER_MINOR 6
+#define VER_MINOR 7
 #define VER_REVISION 0
 
 // Version identifier for network games.
diff --git a/wadsrc/static/shaders/glsl/main.fp b/wadsrc/static/shaders/glsl/main.fp
index 228d7b02d8..f096d0dd7d 100644
--- a/wadsrc/static/shaders/glsl/main.fp
+++ b/wadsrc/static/shaders/glsl/main.fp
@@ -451,7 +451,7 @@ vec3 AmbientOcclusionColor()
 	//
 	if (uFogEnabled == -1) 
 	{
-		fogdist = pixelpos.w;
+		fogdist = max(16.0, pixelpos.w);
 	}
 	else 
 	{
@@ -489,7 +489,7 @@ void main()
 		{
 			if (uFogEnabled == 1 || uFogEnabled == -1) 
 			{
-				fogdist = pixelpos.w;
+				fogdist = max(16.0, pixelpos.w);
 			}
 			else 
 			{
diff --git a/wadsrc/static/zscript/hexen/spike.txt b/wadsrc/static/zscript/hexen/spike.txt
index cb8df17e27..a411dbf3f6 100644
--- a/wadsrc/static/zscript/hexen/spike.txt
+++ b/wadsrc/static/zscript/hexen/spike.txt
@@ -179,26 +179,29 @@ class ThrustFloor : Actor
 		while (it.Next())
 		{
 			let targ = it.thing;
-			double blockdist = radius + it.thing.radius;
-			if (abs(targ.pos.x - it.Position.X) >= blockdist || abs(targ.pos.y - it.Position.Y) >= blockdist)
-				continue;
-
-			// Q: Make this z-aware for everything? It never was before.
-			if (targ.pos.z + targ.height < pos.z || targ.pos.z > pos.z + height)
+			if (targ != null)
 			{
-				if (CurSector.PortalGroup != targ.CurSector.PortalGroup)
+				double blockdist = radius + targ.radius;
+				if (abs(targ.pos.x - it.Position.X) >= blockdist || abs(targ.pos.y - it.Position.Y) >= blockdist)
 					continue;
+
+				// Q: Make this z-aware for everything? It never was before.
+				if (targ.pos.z + targ.height < pos.z || targ.pos.z > pos.z + height)
+				{
+					if (CurSector.PortalGroup != targ.CurSector.PortalGroup)
+						continue;
+				}
+
+				if (!targ.bShootable)
+					continue;
+
+				if (targ == self)
+					continue;	// don't clip against self
+
+				int newdam = targ.DamageMobj (self, self, 10001, 'Crush');
+				targ.TraceBleed (newdam > 0 ? newdam : 10001, null);
+				args[1] = 1;	// Mark thrust thing as bloody
 			}
-
-			if (!targ.bShootable)
-				continue;
-
-			if (targ == self)
-				continue;	// don't clip against self
-
-			int newdam = targ.DamageMobj (self, self, 10001, 'Crush');
-			targ.TraceBleed (newdam > 0 ? newdam : 10001, null);
-			args[1] = 1;	// Mark thrust thing as bloody
 		}
 	}
 }
diff --git a/wadsrc/static/zscript/level_compatibility.txt b/wadsrc/static/zscript/level_compatibility.txt
index a932a0b185..7bc2b017a5 100644
--- a/wadsrc/static/zscript/level_compatibility.txt
+++ b/wadsrc/static/zscript/level_compatibility.txt
@@ -605,6 +605,28 @@ class LevelCompatibility play
 				}
 				break;
 			}
+			
+			case '57386AEF275684BA06756359B08F4391': // Perdition's Gate MAP03
+			{
+				// Stairs where one sector is too thin to score.
+				SetSectorSpecial(227, 0);
+				break;
+			}
+			
+			case 'F1A9938C4FC3906A582AB7D5088B5F87': // Perdition's Gate MAP12
+			{
+				// Sector unintentionally left as a secret near switch
+				SetSectorSpecial(112, 0);
+				break;
+			}
+			
+			case '5C419E581D9570F44A24163A83032086': // Perdition's Gate MAP27
+			{
+				// Sectors unintentionally left as secrets and cannot be scored
+				SetSectorSpecial(338, 0);
+				SetSectorSpecial(459, 0);
+				break;
+			}
 
 			case 'FCCA97FC851F6473EAA069F74247B317': // pg-raw.wad map31
 			{
@@ -621,8 +643,59 @@ class LevelCompatibility play
 				break;
 			}
 			
-			case '712BB4CFBD0753178CA0C6814BE4C288': // beta version of map12 BTSX_E1 - patch some rendering glitches that are problematic to detect
+			case '5379C080299EB961792B50AD96821543': // Hell to Pay MAP14
 			{
+				// Two secrets are unreachable without jumping and crouching.
+				SetSectorSpecial(82, 0);
+				SetSectorSpecial(83, 0);
+				break;
+			}
+			
+			case '7837B5334A277F107515D649BCEFB682': // Hell to Pay MAP22
+			{
+				// Four enemies (six if multiplayer) never spawn in the map,
+				// so the lines closest to them should teleport them instead.
+				SetLineSpecial(1835, Teleport, 0, 40);
+				SetLineActivation(1835, SPAC_MCross);
+				SetLineFlags(1835, Line.ML_REPEAT_SPECIAL);
+				
+				SetLineSpecial(1847, Teleport, 0, 40);
+				SetLineActivation(1847, SPAC_MCross);
+				SetLineFlags(1847, Line.ML_REPEAT_SPECIAL);
+				break;
+			}
+			
+			case '1A1AB6415851B9F17715A0C36412752E': // Hell to Pay MAP24
+			{
+				// Remove Chaingunner far below the map, making 100% kills
+				// impractical.
+				SetThingFlags(70, 0);
+				break;
+			}
+			
+			case 'A7ACB57A2CAF17434D0DFE0FAC0E0480': // Hell to Pay MAP28
+			{
+				// Three Lost Souls placed outside the map for some reason.
+				for(int i=0; i<3; i++)
+				{
+					SetThingFlags(217+i, 0);
+				}
+				break;
+			}
+			
+			case '2F1A18633C30E938B50B6D928C730CB6': // Hell to Pay MAP29
+			{
+				// Three Lost Souls placed outside the map, again...
+				for(int i=0; i<3; i++)
+				{
+					SetThingFlags(239+i, 0);
+				}
+				break;
+			}
+			
+			case '712BB4CFBD0753178CA0C6814BE4C288': // beta version of map12 BTSX_E1
+			{
+				// patch some rendering glitches that are problematic to detect
 				AddSectorTag(545, 32000);
 				AddSectorTag(1618, 32000);
 				SetLineSpecial(2853, Sector_Set3DFloor, 32000, 4);