diff --git a/src/if_perl.xs b/src/if_perl.xs
index 56e0eb3..f0baabf 100644
--- a/src/if_perl.xs
+++ b/src/if_perl.xs
@@ -155,7 +155,7 @@
 # define Perl_set_context dll_Perl_set_context
 # if (PERL_REVISION == 5) && (PERL_VERSION >= 14)
 # define Perl_sv_2bool_flags dll_Perl_sv_2bool_flags
-# define Perl_xs_apiversion_bootcheck dll_Perl_xs_apiversion_bootcheck 
+# define Perl_xs_apiversion_bootcheck dll_Perl_xs_apiversion_bootcheck
 # else
 # define Perl_sv_2bool dll_Perl_sv_2bool
 # endif
@@ -225,6 +225,9 @@
 # define Perl_call_list dll_Perl_call_list
 # define Perl_Iscopestack_ix_ptr dll_Perl_Iscopestack_ix_ptr
 # define Perl_Iunitcheckav_ptr dll_Perl_Iunitcheckav_ptr
+# if (PERL_REVISION == 5) && (PERL_VERSION >= 14)
+#  define PL_thr_key *dll_PL_thr_key
+# endif
 
 /*
  * Declare HANDLE for perl.dll and function pointers.
@@ -335,6 +338,7 @@
 #endif
 
 #if (PERL_REVISION == 5) && (PERL_VERSION >= 14)
+static perl_key* dll_PL_thr_key;
 #else
 static GV** (*Perl_Idefgv_ptr)(register PerlInterpreter*);
 static GV** (*Perl_Ierrgv_ptr)(register PerlInterpreter*);
@@ -453,6 +457,7 @@
 # endif
 #endif
 #if (PERL_REVISION == 5) && (PERL_VERSION >= 14)
+    {"PL_thr_key", (PERL_PROC*)&dll_PL_thr_key},
 #else
     {"Perl_Idefgv_ptr", (PERL_PROC*)&Perl_Idefgv_ptr},
     {"Perl_Ierrgv_ptr", (PERL_PROC*)&Perl_Ierrgv_ptr},
diff --git a/src/version.c b/src/version.c
index 4c93e3a..61e9c0b 100644
--- a/src/version.c
+++ b/src/version.c
@@ -720,6 +720,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    668,
+/**/
     667,
 /**/
     666,