diff --git a/docs/index.rst b/docs/index.rst
index a1607f6..bffe100 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -55,7 +55,7 @@ about compiling Godot can be found in `Godot documentation
 Installing Nim
 -------------
 
-The library requires Nim version 0.17.2 or newer, which you can get here:
+The library requires Nim version 0.18.0 or newer, which you can get here:
 https://nim-lang.org/install.html
 
 Make sure you also have ``nimble`` (Nim's package manager) installed.
diff --git a/godot.nimble b/godot.nimble
index 3e778fd..cac30be 100644
--- a/godot.nimble
+++ b/godot.nimble
@@ -1,4 +1,4 @@
-version = "0.6.7"
+version = "0.6.8"
 author = "Xored Software, Inc."
 description = "Godot Engine bindings"
 license = "MIT"
diff --git a/godot/internal/godotarrays.nim b/godot/internal/godotarrays.nim
index 607474f..32bcefa 100644
--- a/godot/internal/godotarrays.nim
+++ b/godot/internal/godotarrays.nim
@@ -136,20 +136,20 @@ proc binarySearchCustom*(self: var GodotArray, val: ptr GodotVariant,
   getGDNativeAPI().arrayBSearchCustom(self, val, obj, funcName, before)
 
 iterator items*(self: GodotArray): GodotVariant =
-  for i in 0..<self.len:
+  for i in 0.cint..<self.len:
     yield self[i]
 
 iterator mitems*(self: var GodotArray): var GodotVariant =
-  for i in 0..<self.len:
+  for i in 0.cint..<self.len:
     yield self.mget(i)[]
 
 iterator pairs*(self: GodotArray): tuple[key: cint, val: GodotVariant] =
-  for i in 0..<self.len:
+  for i in 0.cint..<self.len:
     yield (i, self[i])
 
 iterator mpairs*(self: var GodotArray): tuple[key: cint,
                                               val: var GodotVariant] =
-  for i in 0..<self.len:
+  for i in 0.cint..<self.len:
     yield (i, self.mget(i)[])
 
 proc `$`*(self: GodotArray): string =
diff --git a/godot/internal/godotpoolarrays.nim b/godot/internal/godotpoolarrays.nim
index ec47139..e655adb 100644
--- a/godot/internal/godotpoolarrays.nim
+++ b/godot/internal/godotpoolarrays.nim
@@ -49,11 +49,11 @@ template genPoolArrayAPI(ArrayT, initIdent, DataT,
     getGDNativeAPI().sizeProc(self)
 
   iterator items*(arr: ArrayT): DataT =
-    for i in 0..<arr.len:
+    for i in 0.cint..<arr.len:
       yield arr[i]
 
   iterator pairs*(arr: ArrayT): tuple[key: cint, val: DataT] =
-    for i in 0..<arr.len:
+    for i in 0.cint..<arr.len:
       yield (i, arr[i])
 
 genPoolArrayAPI(GodotPoolByteArray, initGodotPoolByteArray, byte,
diff --git a/godot/nim/godotmacros.nim b/godot/nim/godotmacros.nim
index d484f4d..ef478f9 100644
--- a/godot/nim/godotmacros.nim
+++ b/godot/nim/godotmacros.nim
@@ -53,7 +53,8 @@ proc extractNames(definition: NimNode):
   if definition.kind == nnkIdent:
     result.name = $(definition.ident)
   else:
-    if not (definition.kind == nnkInfix and definition[0].ident == !"of"):
+    if not (definition.kind == nnkInfix and
+            definition[0].ident == toNimIdent("of")):
       parseError(definition, "invalid type definition")
     result.name = $(definition[1].ident)
     case definition[2].kind:
@@ -90,7 +91,7 @@ proc removePragmaNode(statement: NimNode,
   result = nil
   var pragmas = if RoutineNodes.contains(statement.kind): statement.pragma()
                 else: statement[1]
-  let pnameIdent = !pname
+  let pnameIdent = toNimIdent(pname)
   for ident, val, i in pragmas(pragmas):
     if ident == pnameIdent:
       pragmas.del(i)
@@ -103,7 +104,7 @@ proc removePragma(statement: NimNode, pname: string): bool =
     return false
   var pragmas = if RoutineNodes.contains(statement.kind): statement.pragma()
                 else: statement[1]
-  let pnameIdent = !pname
+  let pnameIdent = toNimIdent(pname)
   for ident, val, i in pragmas(pragmas):
     if ident == pnameIdent:
       pragmas.del(i)
@@ -186,7 +187,7 @@ proc parseType(definition, callSite: NimNode): ObjectDecl =
     let option = callSite[i]
     if option.kind != nnkIdent:
       parseError(option, "type specifier expected")
-    if option.ident == !"tool":
+    if option.ident == toNimIdent("tool"):
       isTool = true
     else:
       parseError(option, "valid type specifier expected")
@@ -587,7 +588,7 @@ proc genType(obj: ObjectDecl): NimNode {.compileTime.} =
     let hasReturnValueBool = not (meth.returnType.isNil or
                          meth.returnType.kind == nnkEmpty or
                          (meth.returnType.kind == nnkIdent and
-                          meth.returnType.ident == !"void"))
+                          meth.returnType.ident == toNimIdent("void")))
     let hasReturnValue = if hasReturnValueBool: ident("true")
                          else: ident("false")
     result.add(getAst(