diff --git a/pyproject.toml b/pyproject.toml
index 366628e..3ecd591 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -25,7 +25,7 @@ dependencies = [
     "python-magic",       # XXX review
     "tokenizers",
     "unidecode",          # XXX review
-    "vec64>0.0.2",
+    "vec64>0.0.5",
 ]
 
 [project.urls]
diff --git a/src/dom_tokenizers/internal/base64.py b/src/dom_tokenizers/internal/base64.py
index 14301f1..32929a9 100644
--- a/src/dom_tokenizers/internal/base64.py
+++ b/src/dom_tokenizers/internal/base64.py
@@ -1,7 +1,5 @@
 from base64 import b64decode as _b64decode, _bytes_from_decode_data, binascii
 
-from vec64 import base64_symbol_indexes as _base64_symbol_indexes
-
 
 def b64decode(s, *args, **kwargs) -> bytes:
     fix_padding = kwargs.pop("fix_padding", False)
@@ -16,13 +14,3 @@ def b64decode(s, *args, **kwargs) -> bytes:
     n = len(t) & 3
     t += b"AA=="[n:]
     return _b64decode(t, *args, **kwargs)
-
-
-def base64_symbol_indexes(text: str) -> bytes:
-    try:
-        return _base64_symbol_indexes(text)
-    except UnicodeEncodeError:
-        return _base64_symbol_indexes(text.encode(errors="replace"))
-
-
-base64_symbol_indexes.__doc__ = _base64_symbol_indexes.__doc__
diff --git a/src/dom_tokenizers/pre_tokenizers/splitter.py b/src/dom_tokenizers/pre_tokenizers/splitter.py
index d01db9a..1c61742 100644
--- a/src/dom_tokenizers/pre_tokenizers/splitter.py
+++ b/src/dom_tokenizers/pre_tokenizers/splitter.py
@@ -10,9 +10,10 @@
 import magic
 
 from unidecode import unidecode
+from vec64 import base64_symbol_indexes
 
 from ..internal import json
-from ..internal.base64 import b64decode, base64_symbol_indexes
+from ..internal.base64 import b64decode
 from .base64 import base64_probability
 
 logger = logging.getLogger(__name__)