diff --git a/dll/win32/imm32/ctf.c b/dll/win32/imm32/ctf.c
index f4463cc67f1..1a0e26788ed 100644
--- a/dll/win32/imm32/ctf.c
+++ b/dll/win32/imm32/ctf.c
@@ -8,6 +8,7 @@
 #include "precomp.h"
 #include <msctf.h> /* for ITfLangBarMgr */
 #include <objidl.h> /* for IInitializeSpy */
+#include <compat_undoc.h> /* for BaseCheckAppcompatCache */
 
 WINE_DEFAULT_DEBUG_CHANNEL(imm);
 
@@ -228,13 +229,6 @@ HINSTANCE g_hCtfIme = NULL;
 /* The type of ApphelpCheckIME function in apphelp.dll */
 typedef BOOL (WINAPI *FN_ApphelpCheckIME)(_In_z_ LPCWSTR AppName);
 
-/* FIXME: This is kernel32 function. We have to declare this in some header. */
-BOOL WINAPI
-BaseCheckAppcompatCache(_In_z_ LPCWSTR ApplicationName,
-                        _In_ HANDLE FileHandle,
-                        _In_opt_z_ LPCWSTR Environment,
-                        _Out_ PULONG pdwReason);
-
 /***********************************************************************
  * This function checks whether the app's IME is disabled by application
  * compatibility patcher.
diff --git a/dll/win32/kernel32/client/appcache.c b/dll/win32/kernel32/client/appcache.c
index 0b2ebec1afe..fae424c106a 100644
--- a/dll/win32/kernel32/client/appcache.c
+++ b/dll/win32/kernel32/client/appcache.c
@@ -139,20 +139,122 @@ IsShimInfrastructureDisabled(VOID)
  * @unimplemented
  */
 BOOL
-WINAPI
-BaseCheckAppcompatCache(IN PWCHAR ApplicationName,
-                        IN HANDLE FileHandle,
-                        IN PWCHAR Environment,
-                        OUT PULONG Reason)
+BasepShimCacheCheckBypass(
+    _In_ PCWSTR ApplicationName,
+    _In_ HANDLE FileHandle,
+    _In_opt_ PCWSTR Environment,
+    _In_ BOOL bUnknown,
+    _Out_opt_ PULONG pdwReason)
 {
-    DPRINT("BaseCheckAppcompatCache is UNIMPLEMENTED\n");
-
-    if (Reason) *Reason = 0;
-
-    // We don't know this app.
+    DPRINT("fixme:(%S, %p, %S, %d, %p)\n", ApplicationName, FileHandle, Environment, bUnknown,
+           pdwReason);
     return FALSE;
 }
 
+/*
+ * @implemented
+ */
+BOOL
+BasepShimCacheSearch(
+    _In_ PCWSTR ApplicationName,
+    _In_ HANDLE FileHandle)
+{
+    APPHELP_CACHE_SERVICE_LOOKUP Lookup;
+    RtlInitUnicodeString(&Lookup.ImageName, ApplicationName);
+    Lookup.ImageHandle = FileHandle;
+    return NT_SUCCESS(NtApphelpCacheControl(ApphelpCacheServiceLookup, &Lookup));
+}
+
+/*
+ * @unimplemented
+ */
+BOOL
+BasepCheckCacheExcludeList(
+    _In_ PCWSTR ApplicationName)
+{
+    return FALSE;
+}
+
+/*
+ * @unimplemented
+ */
+BOOL
+BasepCheckCacheExcludeCustom(
+    _In_ PCWSTR ApplicationName)
+{
+    return FALSE;
+}
+
+/*
+ * @implemented
+ */
+VOID
+BasepShimCacheRemoveEntry(
+    _In_ PCWSTR ApplicationName)
+{
+    APPHELP_CACHE_SERVICE_LOOKUP Lookup;
+    RtlInitUnicodeString(&Lookup.ImageName, ApplicationName);
+    Lookup.ImageHandle = INVALID_HANDLE_VALUE;
+    NtApphelpCacheControl(ApphelpCacheServiceRemove, &Lookup);
+}
+
+/*
+ * @unimplemented
+ */
+BOOL
+BasepShimCacheLookup(
+    _In_ PCWSTR ApplicationName,
+    _In_ HANDLE FileHandle)
+{
+    DPRINT("fixme:(%S, %p)\n", ApplicationName, FileHandle);
+
+    if (!BasepShimCacheSearch(ApplicationName, FileHandle))
+        return FALSE;
+
+    if (!BasepCheckCacheExcludeList(ApplicationName) ||
+        !BasepCheckCacheExcludeCustom(ApplicationName))
+    {
+        BasepShimCacheRemoveEntry(ApplicationName);
+        return FALSE;
+    }
+
+    return TRUE;
+}
+
+/*
+ * @implemented
+ */
+BOOL
+WINAPI
+BaseCheckAppcompatCache(
+    _In_ PCWSTR ApplicationName,
+    _In_ HANDLE FileHandle,
+    _In_opt_ PCWSTR Environment,
+    _Out_opt_ PULONG pdwReason)
+{
+    BOOL ret = FALSE;
+    ULONG dwReason;
+
+    DPRINT("(%S, %p, %S, %p)\n", ApplicationName, FileHandle, Environment, pdwReason);
+
+    dwReason = 0;
+    if (BasepShimCacheCheckBypass(ApplicationName, FileHandle, Environment, TRUE, &dwReason))
+    {
+        dwReason |= 2;
+    }
+    else
+    {
+        ret = BasepShimCacheLookup(ApplicationName, FileHandle);
+        if (!ret)
+            dwReason |= 1;
+    }
+
+    if (pdwReason)
+        *pdwReason = dwReason;
+
+    return ret;
+}
+
 static
 VOID
 BaseInitApphelp(VOID)
diff --git a/dll/win32/kernel32/kernel32.spec b/dll/win32/kernel32/kernel32.spec
index 3b41edde6d8..5fe3047cb42 100644
--- a/dll/win32/kernel32/kernel32.spec
+++ b/dll/win32/kernel32/kernel32.spec
@@ -24,7 +24,7 @@
 @ stdcall BackupRead(ptr ptr long ptr long long ptr)
 @ stdcall BackupSeek(ptr long long ptr ptr ptr)
 @ stdcall BackupWrite(ptr ptr long ptr long long ptr)
-@ stdcall BaseCheckAppcompatCache(long long long ptr)
+@ stdcall BaseCheckAppcompatCache(wstr ptr wstr ptr)
 @ stdcall BaseCheckRunApp(long ptr long long long long long long long long)
 @ stdcall BaseCleanupAppcompatCacheSupport(ptr)
 @ stdcall BaseDumpAppcompatCache()
diff --git a/sdk/include/reactos/compat_undoc.h b/sdk/include/reactos/compat_undoc.h
index b0516322a37..cea9930e648 100644
--- a/sdk/include/reactos/compat_undoc.h
+++ b/sdk/include/reactos/compat_undoc.h
@@ -46,4 +46,12 @@ UINT RosGetProcessEffectiveVersion(VOID)
         return (peb->OSMajorVersion << 8) | (peb->OSMinorVersion);
 }
 
+BOOL
+WINAPI
+BaseCheckAppcompatCache(
+    _In_ PCWSTR ApplicationName,
+    _In_ HANDLE FileHandle,
+    _In_opt_ PCWSTR Environment,
+    _Out_opt_ PULONG pdwReason);
+
 #endif // COMPAT_UNDOC_H