diff --git a/nomsu_environment.lua b/nomsu_environment.lua
index 08993ea..08face7 100644
--- a/nomsu_environment.lua
+++ b/nomsu_environment.lua
@@ -170,7 +170,18 @@ nomsu_environment = Importer({
     assert(parse, "No parser found for Nomsu syntax version " .. tostring(syntax_version))
     local tree = parse(nomsu_code, source.filename)
     if tree.shebang then
-      tree.version = tree.version or tree.shebang:match("nomsu %-V[ ]*([%d.]*)")
+      local shebang_version = tree.shebang:match("nomsu %-V[ ]*([%d.]+)")
+      if shebang_version and shebang_version ~= "" then
+        tree.version = tree.version or List((function()
+          local _accum_0 = { }
+          local _len_0 = 1
+          for v in shebang_version:gmatch("%d+") do
+            _accum_0[_len_0] = tonumber(v)
+            _len_0 = _len_0 + 1
+          end
+          return _accum_0
+        end)())
+      end
     end
     return tree
   end,
@@ -288,6 +299,7 @@ nomsu_environment = Importer({
       return self:run(tree)
     elseif SyntaxTree:is_instance(to_run) then
       local filename = to_run.source.filename:gsub("\n.*", "...")
+      local version = to_run.version
       if to_run.type ~= "FileChunks" then
         to_run = {
           to_run
@@ -295,6 +307,7 @@ nomsu_environment = Importer({
       end
       local ret = nil
       for chunk_no, chunk in ipairs(to_run) do
+        chunk.version = version
         local lua = self:compile(chunk)
         lua:declare_locals()
         lua:prepend("-- File: " .. tostring(filename) .. " chunk #" .. tostring(chunk_no) .. "\n")
diff --git a/nomsu_environment.moon b/nomsu_environment.moon
index 7e248c9..7066be1 100644
--- a/nomsu_environment.moon
+++ b/nomsu_environment.moon
@@ -91,7 +91,15 @@ nomsu_environment = Importer{
         assert parse, "No parser found for Nomsu syntax version #{syntax_version}"
         tree = parse(nomsu_code, source.filename)
         if tree.shebang
-            tree.version or= tree.shebang\match("nomsu %-V[ ]*([%d.]*)")
+            shebang_version = tree.shebang\match("nomsu %-V[ ]*([%d.]+)")
+            if shebang_version and shebang_version != ""
+                tree.version or= List[tonumber(v) for v in shebang_version\gmatch("%d+")]
+        --if tree.version and tree.version < NOMSU_VERSION\up_to(#tree.version) and not package.nomsuloaded["compatibility"]
+        --    export loading_compat
+        --    unless loading_compat
+        --        loading_compat = true
+        --        nomsu_environment\export "compatibility"
+        --        loading_compat = false
         return tree
 
     Module: (package_name)=>
@@ -184,6 +192,7 @@ nomsu_environment = Importer{
             return @run(tree)
         elseif SyntaxTree\is_instance(to_run)
             filename = to_run.source.filename\gsub("\n.*", "...")
+            version = to_run.version
             if to_run.type != "FileChunks"
                 to_run = {to_run}
             -- Each chunk's compilation is affected by the code in the previous chunks
@@ -191,6 +200,7 @@ nomsu_environment = Importer{
             -- compiles.
             ret = nil
             for chunk_no, chunk in ipairs to_run
+                chunk.version = version
                 lua = @compile(chunk)
                 lua\declare_locals!
                 lua\prepend "-- File: #{filename} chunk ##{chunk_no}\n"