diff --git a/src/gui_w32.c b/src/gui_w32.c
index 9b77f7d..a36f976 100644
--- a/src/gui_w32.c
+++ b/src/gui_w32.c
@@ -992,7 +992,7 @@
 			    SendMessage(lpdi->hdr.hwndFrom, TTM_SETMAXTIPWIDTH,
 								      0, 500);
 
-			    tt_text = enc_to_ucs2(str, NULL);
+			    tt_text = enc_to_utf16(str, NULL);
 			    lpdi->lpszText = tt_text;
 			    /* can't show tooltip if failed */
 			}
@@ -1935,7 +1935,7 @@
     if (buf == NULL)
 	return NULL;
 
-    convbuf = ucs2_to_enc(buf, lenp);
+    convbuf = utf16_to_enc(buf, lenp);
     pImmReleaseContext(hwnd, hIMC);
     vim_free(buf);
     return convbuf;
@@ -2566,7 +2566,7 @@
 	    {
 		/* 'encoding' differs from active codepage: convert menu name
 		 * and use wide function */
-		wn = enc_to_ucs2(menu->name, NULL);
+		wn = enc_to_utf16(menu->name, NULL);
 		if (wn != NULL)
 		{
 		    MENUITEMINFOW	infow;
@@ -2728,7 +2728,7 @@
 	{
 	    /* 'encoding' differs from active codepage: convert menu item name
 	     * and use wide function */
-	    wn = enc_to_ucs2(menu->name, NULL);
+	    wn = enc_to_utf16(menu->name, NULL);
 	    if (wn != NULL)
 	    {
 		n = InsertMenuW(parent->submenu_id, (UINT)idx,
@@ -3570,7 +3570,7 @@
     if (enc_codepage == 0 && (int)GetACP() != enc_codepage)
     {
 	/* Not a codepage, use our own conversion function. */
-	wn = enc_to_ucs2(lpAnsiIn, NULL);
+	wn = enc_to_utf16(lpAnsiIn, NULL);
 	if (wn != NULL)
 	{
 	    wcscpy(lpWCStr, wn);
diff --git a/src/gui_w48.c b/src/gui_w48.c
index 53dbad1..08dcb2d 100644
--- a/src/gui_w48.c
+++ b/src/gui_w48.c
@@ -547,7 +547,7 @@
 	else
 	{
 	    len = 1;
-	    ws = ucs2_to_enc(wstring, &len);
+	    ws = utf16_to_enc(wstring, &len);
 	    if (ws == NULL)
 		len = 0;
 	    else
@@ -2128,7 +2128,7 @@
     {
 	/* 'encoding' differs from active codepage: convert text and use wide
 	 * function */
-	wstr = enc_to_ucs2(str, &wlen);
+	wstr = enc_to_utf16(str, &wlen);
 	if (wstr != NULL)
 	{
 	    n = GetTextExtentPointW(hdc, wstr, wlen, &size);
@@ -2252,7 +2252,7 @@
     {
 	/* 'encoding' differs from active codepage: convert menu name
 	 * and use wide function */
-	wn = enc_to_ucs2(item_text, NULL);
+	wn = enc_to_utf16(item_text, NULL);
 	if (wn != NULL)
 	{
 	    MENUITEMINFOW	infow;
@@ -2422,7 +2422,7 @@
 	if (use_unicode)
 	{
 	    /* Need to go through Unicode. */
-	    wstr = enc_to_ucs2(NameBuff, NULL);
+	    wstr = enc_to_utf16(NameBuff, NULL);
 	    if (wstr != NULL)
 	    {
 		TCITEMW		tiw;
@@ -2521,8 +2521,8 @@
 	WCHAR	*wbuf;
 	int	n;
 
-	/* Convert the title from 'encoding' to ucs2. */
-	wbuf = (WCHAR *)enc_to_ucs2((char_u *)title, NULL);
+	/* Convert the title from 'encoding' to UTF-16. */
+	wbuf = (WCHAR *)enc_to_utf16((char_u *)title, NULL);
 	if (wbuf != NULL)
 	{
 	    n = SetWindowTextW(hwnd, wbuf);
@@ -3222,7 +3222,7 @@
 	char_u *initdir,
 	char_u *filter)
 {
-    /* We always use the wide function.  This means enc_to_ucs2() must work,
+    /* We always use the wide function.  This means enc_to_utf16() must work,
      * otherwise it fails miserably! */
     OPENFILENAMEW	fileStruct;
     WCHAR		fileBuf[MAXPATHL];
@@ -3238,7 +3238,7 @@
 	fileBuf[0] = NUL;
     else
     {
-	wp = enc_to_ucs2(dflt, NULL);
+	wp = enc_to_utf16(dflt, NULL);
 	if (wp == NULL)
 	    fileBuf[0] = NUL;
 	else
@@ -3263,11 +3263,11 @@
 #endif
 
     if (title != NULL)
-	titlep = enc_to_ucs2(title, NULL);
+	titlep = enc_to_utf16(title, NULL);
     fileStruct.lpstrTitle = titlep;
 
     if (ext != NULL)
-	extp = enc_to_ucs2(ext, NULL);
+	extp = enc_to_utf16(ext, NULL);
     fileStruct.lpstrDefExt = extp;
 
     fileStruct.lpstrFile = fileBuf;
@@ -3278,7 +3278,7 @@
     if (initdir != NULL && *initdir != NUL)
     {
 	/* Must have backslashes here, no matter what 'shellslash' says */
-	initdirp = enc_to_ucs2(initdir, NULL);
+	initdirp = enc_to_utf16(initdir, NULL);
 	if (initdirp != NULL)
 	{
 	    for (wp = initdirp; *wp != NUL; ++wp)
@@ -3318,7 +3318,7 @@
     vim_free(extp);
 
     /* Convert from UCS2 to 'encoding'. */
-    p = ucs2_to_enc(fileBuf, NULL);
+    p = utf16_to_enc(fileBuf, NULL);
     if (p != NULL)
 	/* when out of memory we get garbage for non-ASCII chars */
 	STRCPY(fileBuf, p);
@@ -3518,7 +3518,7 @@
 	{
 #ifdef FEAT_MBYTE
 	    if (DragQueryFileW(hDrop, i, wszFile, BUFPATHLEN) > 0)
-		fnames[i] = ucs2_to_enc(wszFile, NULL);
+		fnames[i] = utf16_to_enc(wszFile, NULL);
 	    else
 #endif
 	    {
diff --git a/src/mbyte.c b/src/mbyte.c
index b7114e8..a2ffd7e 100644
--- a/src/mbyte.c
+++ b/src/mbyte.c
@@ -6101,7 +6101,7 @@
 
 	    /* 1. codepage/UTF-8  ->  ucs-2. */
 	    if (vcp->vc_cpfrom == 0)
-		tmp_len = utf8_to_ucs2(ptr, len, NULL, NULL);
+		tmp_len = utf8_to_utf16(ptr, len, NULL, NULL);
 	    else
 		tmp_len = MultiByteToWideChar(vcp->vc_cpfrom, 0,
 							      ptr, len, 0, 0);
@@ -6109,13 +6109,13 @@
 	    if (tmp == NULL)
 		break;
 	    if (vcp->vc_cpfrom == 0)
-		utf8_to_ucs2(ptr, len, tmp, unconvlenp);
+		utf8_to_utf16(ptr, len, tmp, unconvlenp);
 	    else
 		MultiByteToWideChar(vcp->vc_cpfrom, 0, ptr, len, tmp, tmp_len);
 
 	    /* 2. ucs-2  ->  codepage/UTF-8. */
 	    if (vcp->vc_cpto == 0)
-		retlen = ucs2_to_utf8(tmp, tmp_len, NULL);
+		retlen = utf16_to_utf8(tmp, tmp_len, NULL);
 	    else
 		retlen = WideCharToMultiByte(vcp->vc_cpto, 0,
 						    tmp, tmp_len, 0, 0, 0, 0);
@@ -6123,7 +6123,7 @@
 	    if (retval != NULL)
 	    {
 		if (vcp->vc_cpto == 0)
-		    ucs2_to_utf8(tmp, tmp_len, retval);
+		    utf16_to_utf8(tmp, tmp_len, retval);
 		else
 		    WideCharToMultiByte(vcp->vc_cpto, 0,
 					  tmp, tmp_len, retval, retlen, 0, 0);
diff --git a/src/misc1.c b/src/misc1.c
index 727951f..0487290 100644
--- a/src/misc1.c
+++ b/src/misc1.c
@@ -8728,7 +8728,7 @@
 	/* The active codepage differs from 'encoding'.  Attempt using the
 	 * wide function.  If it fails because it is not implemented fall back
 	 * to the non-wide version (for Windows 98) */
-	wn = enc_to_ucs2(buf, NULL);
+	wn = enc_to_utf16(buf, NULL);
 	if (wn != NULL)
 	{
 	    hFind = FindFirstFileW(wn, &wfb);
@@ -8756,7 +8756,7 @@
 #ifdef WIN3264
 # ifdef FEAT_MBYTE
 	if (wn != NULL)
-	    p = ucs2_to_enc(wfb.cFileName, NULL);   /* p is allocated here */
+	    p = utf16_to_enc(wfb.cFileName, NULL);   /* p is allocated here */
 	else
 # endif
 	    p = (char_u *)fb.cFileName;
@@ -8830,7 +8830,7 @@
 	    if (wn != NULL)
 	    {
 		vim_free(wn);
-		wn = enc_to_ucs2(buf, NULL);
+		wn = enc_to_utf16(buf, NULL);
 		if (wn != NULL)
 		    hFind = FindFirstFileW(wn, &wfb);
 	    }
diff --git a/src/os_mswin.c b/src/os_mswin.c
index b2eee92..32a068f 100644
--- a/src/os_mswin.c
+++ b/src/os_mswin.c
@@ -309,7 +309,7 @@
 	if (enc_codepage >= 0 && (int)GetACP() != enc_codepage)
 	{
 	    /* Convert the title from 'encoding' to the active codepage. */
-	    WCHAR	*wp = enc_to_ucs2(title, NULL);
+	    WCHAR	*wp = enc_to_utf16(title, NULL);
 	    int	n;
 
 	    if (wp != NULL)
@@ -406,10 +406,10 @@
 	     * - invoke _wfullpath()
 	     * - convert the result from UCS2 to 'encoding'.
 	     */
-	    wname = enc_to_ucs2(fname, NULL);
+	    wname = enc_to_utf16(fname, NULL);
 	    if (wname != NULL && _wfullpath(wbuf, wname, MAX_PATH - 1) != NULL)
 	    {
-		cname = ucs2_to_enc((short_u *)wbuf, NULL);
+		cname = utf16_to_enc((short_u *)wbuf, NULL);
 		if (cname != NULL)
 		{
 		    vim_strncpy(buf, cname, len - 1);
@@ -507,7 +507,7 @@
 # endif
        )
     {
-	WCHAR	*wp = enc_to_ucs2(buf, NULL);
+	WCHAR	*wp = enc_to_utf16(buf, NULL);
 	int	n;
 
 	if (wp != NULL)
@@ -668,7 +668,7 @@
 #ifdef FEAT_MBYTE
     if (enc_codepage >= 0 && (int)GetACP() != enc_codepage)
     {
-	WCHAR	*p = enc_to_ucs2(path, NULL);
+	WCHAR	*p = enc_to_utf16(path, NULL);
 	int	n;
 
 	if (p != NULL)
@@ -891,19 +891,20 @@
 
 #if defined(FEAT_MBYTE) || defined(PROTO)
 /*
- * Convert an UTF-8 string to UCS-2.
+ * Convert an UTF-8 string to UTF-16.
  * "instr[inlen]" is the input.  "inlen" is in bytes.
- * When "outstr" is NULL only return the number of UCS-2 words produced.
+ * When "outstr" is NULL only return the number of UTF-16 words produced.
  * Otherwise "outstr" must be a buffer of sufficient size.
- * Returns the number of UCS-2 words produced.
+ * Returns the number of UTF-16 words produced.
  */
     int
-utf8_to_ucs2(char_u *instr, int inlen, short_u *outstr, int *unconvlenp)
+utf8_to_utf16(char_u *instr, int inlen, short_u *outstr, int *unconvlenp)
 {
     int		outlen = 0;
     char_u	*p = instr;
     int		todo = inlen;
     int		l;
+    int		ch;
 
     while (todo > 0)
     {
@@ -917,8 +918,19 @@
 	    break;
 	}
 
-	if (outstr != NULL)
-	    *outstr++ = utf_ptr2char(p);
+	ch = utf_ptr2char(p);
+	if (ch >= 0x10000)
+	{
+	    /* non-BMP character, encoding with surrogate pairs */
+	    ++outlen;
+	    if (outstr != NULL)
+	    {
+		*outstr++ = (0xD800 - (0x10000 >> 10)) + (ch >> 10);
+		*outstr++ = 0xDC00 | (ch & 0x3FF);
+	    }
+	}
+	else if (outstr != NULL)
+	    *outstr++ = ch;
 	++outlen;
 	p += l;
 	todo -= l;
@@ -928,29 +940,42 @@
 }
 
 /*
- * Convert an UCS-2 string to UTF-8.
- * The input is "instr[inlen]" with "inlen" in number of ucs-2 words.
+ * Convert an UTF-16 string to UTF-8.
+ * The input is "instr[inlen]" with "inlen" in number of UTF-16 words.
  * When "outstr" is NULL only return the required number of bytes.
  * Otherwise "outstr" must be a buffer of sufficient size.
  * Return the number of bytes produced.
  */
     int
-ucs2_to_utf8(short_u *instr, int inlen, char_u *outstr)
+utf16_to_utf8(short_u *instr, int inlen, char_u *outstr)
 {
     int		outlen = 0;
     int		todo = inlen;
     short_u	*p = instr;
     int		l;
+    int		ch, ch2;
 
     while (todo > 0)
     {
+	ch = *p;
+	if (ch >= 0xD800 && ch <= 0xDBFF && todo > 1)
+	{
+	    /* surrogate pairs handling */
+	    ch2 = p[1];
+	    if (ch2 >= 0xDC00 && ch2 <= 0xDFFF)
+	    {
+		ch = ((ch - 0xD800) << 10) + (ch2 & 0x3FF) + 0x10000;
+		++p;
+		--todo;
+	    }
+	}
 	if (outstr != NULL)
 	{
-	    l = utf_char2bytes(*p, outstr);
+	    l = utf_char2bytes(ch, outstr);
 	    outstr += l;
 	}
 	else
-	    l = utf_char2len(*p);
+	    l = utf_char2len(ch);
 	++p;
 	outlen += l;
 	--todo;
@@ -1079,14 +1104,14 @@
  */
 
 /*
- * Convert "str" from 'encoding' to UCS-2.
+ * Convert "str" from 'encoding' to UTF-16.
  * Input in "str" with length "*lenp".  When "lenp" is NULL, use strlen().
  * Output is returned as an allocated string.  "*lenp" is set to the length of
  * the result.  A trailing NUL is always added.
  * Returns NULL when out of memory.
  */
     short_u *
-enc_to_ucs2(char_u *str, int *lenp)
+enc_to_utf16(char_u *str, int *lenp)
 {
     vimconv_T	conv;
     WCHAR	*ret;
@@ -1102,7 +1127,7 @@
 
     if (enc_codepage > 0)
     {
-	/* We can do any CP### -> UCS-2 in one pass, and we can do it
+	/* We can do any CP### -> UTF-16 in one pass, and we can do it
 	 * without iconv() (convert_* may need iconv). */
 	MultiByteToWideChar_alloc(enc_codepage, 0, str, *lenp, &ret, &length);
     }
@@ -1123,11 +1148,11 @@
 	}
 	convert_setup(&conv, NULL, NULL);
 
-	length = utf8_to_ucs2(str, *lenp, NULL, NULL);
+	length = utf8_to_utf16(str, *lenp, NULL, NULL);
 	ret = (WCHAR *)alloc((unsigned)((length + 1) * sizeof(WCHAR)));
 	if (ret != NULL)
 	{
-	    utf8_to_ucs2(str, *lenp, (short_u *)ret, NULL);
+	    utf8_to_utf16(str, *lenp, (short_u *)ret, NULL);
 	    ret[length] = 0;
 	}
 
@@ -1139,7 +1164,7 @@
 }
 
 /*
- * Convert an UCS-2 string to 'encoding'.
+ * Convert an UTF-16 string to 'encoding'.
  * Input in "str" with length (counted in wide characters) "*lenp".  When
  * "lenp" is NULL, use wcslen().
  * Output is returned as an allocated string.  If "*lenp" is not NULL it is
@@ -1147,7 +1172,7 @@
  * Returns NULL when out of memory.
  */
     char_u *
-ucs2_to_enc(short_u *str, int *lenp)
+utf16_to_enc(short_u *str, int *lenp)
 {
     vimconv_T	conv;
     char_u	*utf8_str = NULL, *enc_str = NULL;
@@ -1161,7 +1186,7 @@
 
     if (enc_codepage > 0)
     {
-	/* We can do any UCS-2 -> CP### in one pass. */
+	/* We can do any UTF-16 -> CP### in one pass. */
 	int length;
 
 	WideCharToMultiByte_alloc(enc_codepage, 0, str, *lenp,
@@ -1171,10 +1196,10 @@
     }
 
     /* Avoid allocating zero bytes, it generates an error message. */
-    utf8_str = alloc(ucs2_to_utf8(str, *lenp == 0 ? 1 : *lenp, NULL));
+    utf8_str = alloc(utf16_to_utf8(str, *lenp == 0 ? 1 : *lenp, NULL));
     if (utf8_str != NULL)
     {
-	*lenp = ucs2_to_utf8(str, *lenp, utf8_str);
+	*lenp = utf16_to_utf8(str, *lenp, utf8_str);
 
 	/* We might be called before we have p_enc set up. */
 	conv.vc_type = CONV_NONE;
@@ -1308,7 +1333,7 @@
 		    if (hMemWstr[str_size] == NUL)
 			break;
 	    }
-	    to_free = str = ucs2_to_enc((short_u *)hMemWstr, &str_size);
+	    to_free = str = utf16_to_enc((short_u *)hMemWstr, &str_size);
 	    GlobalUnlock(hMemW);
 	}
     }
@@ -1340,7 +1365,7 @@
 
 # if defined(FEAT_MBYTE) && defined(WIN3264)
 	    /* The text is in the active codepage.  Convert to 'encoding',
-	     * going through UCS-2. */
+	     * going through UTF-16. */
 	    acp_to_enc(str, str_size, &to_free, &maxlen);
 	    if (to_free != NULL)
 	    {
@@ -1404,7 +1429,7 @@
     if (widestr != NULL)
     {
 	++*outlen;	/* Include the 0 after the string */
-	*out = ucs2_to_enc((short_u *)widestr, outlen);
+	*out = utf16_to_enc((short_u *)widestr, outlen);
 	vim_free(widestr);
     }
 }
@@ -1466,9 +1491,9 @@
 	WCHAR		*out;
 	int		len = metadata.txtlen;
 
-	/* Convert the text to UCS-2. This is put on the clipboard as
+	/* Convert the text to UTF-16. This is put on the clipboard as
 	 * CF_UNICODETEXT. */
-	out = (WCHAR *)enc_to_ucs2(str, &len);
+	out = (WCHAR *)enc_to_utf16(str, &len);
 	if (out != NULL)
 	{
 	    WCHAR *lpszMemW;
@@ -1488,7 +1513,7 @@
 	    WideCharToMultiByte(GetACP(), 0, out, len,
 						  str, metadata.txtlen, 0, 0);
 
-	    /* Allocate memory for the UCS-2 text, add one NUL word to
+	    /* Allocate memory for the UTF-16 text, add one NUL word to
 	     * terminate the string. */
 	    hMemW = (LPSTR)GlobalAlloc(GMEM_MOVEABLE | GMEM_DDESHARE,
 						   (len + 1) * sizeof(WCHAR));
diff --git a/src/os_win32.c b/src/os_win32.c
index 4844299..3d0ba7d 100644
--- a/src/os_win32.c
+++ b/src/os_win32.c
@@ -1587,7 +1587,7 @@
 #ifdef FEAT_MBYTE
     if (enc_codepage >= 0 && (int)GetACP() != enc_codepage)
     {
-	WCHAR	*p = enc_to_ucs2(name, NULL);
+	WCHAR	*p = enc_to_utf16(name, NULL);
 	WCHAR	fnamew[_MAX_PATH];
 	WCHAR	*dumw;
 	long	n;
@@ -2440,7 +2440,7 @@
 
 	if (GetCurrentDirectoryW(_MAX_PATH, wbuf) != 0)
 	{
-	    char_u  *p = ucs2_to_enc(wbuf, NULL);
+	    char_u  *p = utf16_to_enc(wbuf, NULL);
 
 	    if (p != NULL)
 	    {
@@ -2466,7 +2466,7 @@
 #ifdef FEAT_MBYTE
     if (enc_codepage >= 0 && (int)GetACP() != enc_codepage)
     {
-	WCHAR	*p = enc_to_ucs2(name, NULL);
+	WCHAR	*p = enc_to_utf16(name, NULL);
 	long	n;
 
 	if (p != NULL)
@@ -2495,7 +2495,7 @@
 #ifdef FEAT_MBYTE
     if (enc_codepage >= 0 && (int)GetACP() != enc_codepage)
     {
-	WCHAR	*p = enc_to_ucs2(name, NULL);
+	WCHAR	*p = enc_to_utf16(name, NULL);
 	long	n;
 
 	if (p != NULL)
@@ -2522,7 +2522,7 @@
     WCHAR	*p = NULL;
 
     if (enc_codepage >= 0 && (int)GetACP() != enc_codepage)
-	p = enc_to_ucs2(name, NULL);
+	p = enc_to_utf16(name, NULL);
 #endif
 
 #ifdef FEAT_MBYTE
@@ -2590,7 +2590,7 @@
     WCHAR	*wn = NULL;
 
     if (enc_codepage >= 0 && (int)GetACP() != enc_codepage)
-	wn = enc_to_ucs2(fname, NULL);
+	wn = enc_to_utf16(fname, NULL);
     if (wn != NULL)
     {
 	hFile = CreateFileW(wn,		/* file name */
@@ -4239,7 +4239,7 @@
 
     if (enc_codepage >= 0 && (int)GetACP() != enc_codepage)
     {
-	wn = enc_to_ucs2(name, NULL);
+	wn = enc_to_utf16(name, NULL);
 	if (wn != NULL)
 	{
 	    SetFileAttributesW(wn, FILE_ATTRIBUTE_NORMAL);
@@ -4382,8 +4382,8 @@
 
     if (enc_codepage >= 0 && (int)GetACP() != enc_codepage)
     {
-	wold = enc_to_ucs2((char_u *)pszOldFile, NULL);
-	wnew = enc_to_ucs2((char_u *)pszNewFile, NULL);
+	wold = enc_to_utf16((char_u *)pszOldFile, NULL);
+	wnew = enc_to_utf16((char_u *)pszNewFile, NULL);
 	if (wold != NULL && wnew != NULL)
 	    retval = mch_wrename(wold, wnew);
 	vim_free(wold);
@@ -4492,7 +4492,7 @@
     WCHAR	*wn = NULL;
 
     if (enc_codepage >= 0 && (int)GetACP() != enc_codepage)
-	wn = enc_to_ucs2(n, NULL);
+	wn = enc_to_utf16(n, NULL);
 #endif
 
     if (mch_isdir(n))
@@ -4618,7 +4618,7 @@
 
 #if defined(FEAT_MBYTE) || defined(PROTO)
 /*
- * Version of open() that may use ucs2 file name.
+ * Version of open() that may use UTF-16 file name.
  */
     int
 mch_open(char *name, int flags, int mode)
@@ -4630,7 +4630,7 @@
 
     if (enc_codepage >= 0 && (int)GetACP() != enc_codepage)
     {
-	wn = enc_to_ucs2(name, NULL);
+	wn = enc_to_utf16(name, NULL);
 	if (wn != NULL)
 	{
 	    f = _wopen(wn, flags, mode);
@@ -4648,7 +4648,7 @@
 }
 
 /*
- * Version of fopen() that may use ucs2 file name.
+ * Version of fopen() that may use UTF-16 file name.
  */
     FILE *
 mch_fopen(char *name, char *mode)
@@ -4675,8 +4675,8 @@
 	else if (newMode == 'b')
 	    _set_fmode(_O_BINARY);
 # endif
-	wn = enc_to_ucs2(name, NULL);
-	wm = enc_to_ucs2(mode, NULL);
+	wn = enc_to_utf16(name, NULL);
+	wm = enc_to_utf16(mode, NULL);
 	if (wn != NULL && wm != NULL)
 	    f = _wfopen(wn, wm);
 	vim_free(wn);
@@ -4776,8 +4776,8 @@
     int			len;
 
     /* Convert the file names to wide characters. */
-    fromw = enc_to_ucs2(from, NULL);
-    tow = enc_to_ucs2(to, NULL);
+    fromw = enc_to_utf16(from, NULL);
+    tow = enc_to_utf16(to, NULL);
     if (fromw != NULL && tow != NULL)
     {
 	/* Open the file for reading. */
@@ -5122,7 +5122,7 @@
     for (i = 0; i < used_file_count; ++i)
     {
 	idx = used_file_indexes[i];
-	str = ucs2_to_enc(ArglistW[idx], NULL);
+	str = utf16_to_enc(ArglistW[idx], NULL);
 	if (str != NULL)
 	{
 #ifdef FEAT_DIFF
diff --git a/src/proto/os_mswin.pro b/src/proto/os_mswin.pro
index 752a27b..2bf927d 100644
--- a/src/proto/os_mswin.pro
+++ b/src/proto/os_mswin.pro
@@ -22,14 +22,14 @@
 int can_end_termcap_mode __ARGS((int give_msg));
 int mch_screenmode __ARGS((char_u *arg));
 int mch_libcall __ARGS((char_u *libname, char_u *funcname, char_u *argstring, int argint, char_u **string_result, int *number_result));
-int utf8_to_ucs2 __ARGS((char_u *instr, int inlen, short_u *outstr, int *unconvlenp));
-int ucs2_to_utf8 __ARGS((short_u *instr, int inlen, char_u *outstr));
+int utf8_to_utf16 __ARGS((char_u *instr, int inlen, short_u *outstr, int *unconvlenp));
+int utf16_to_utf8 __ARGS((short_u *instr, int inlen, char_u *outstr));
 void MultiByteToWideChar_alloc __ARGS((UINT cp, DWORD flags, LPCSTR in, int inlen, LPWSTR *out, int *outlen));
 void WideCharToMultiByte_alloc __ARGS((UINT cp, DWORD flags, LPCWSTR in, int inlen, LPSTR *out, int *outlen, LPCSTR def, LPBOOL useddef));
 int clip_mch_own_selection __ARGS((VimClipboard *cbd));
 void clip_mch_lose_selection __ARGS((VimClipboard *cbd));
-short_u *enc_to_ucs2 __ARGS((char_u *str, int *lenp));
-char_u *ucs2_to_enc __ARGS((short_u *str, int *lenp));
+short_u *enc_to_utf16 __ARGS((char_u *str, int *lenp));
+char_u *utf16_to_enc __ARGS((short_u *str, int *lenp));
 void clip_mch_request_selection __ARGS((VimClipboard *cbd));
 void acp_to_enc __ARGS((char_u *str, int str_size, char_u **out, int *outlen));
 void clip_mch_set_selection __ARGS((VimClipboard *cbd));
diff --git a/src/version.c b/src/version.c
index ee0240e..242041f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -677,6 +677,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    49,
+/**/
     48,
 /**/
     47,