diff --git a/pyproject.toml b/pyproject.toml
index 91f1464df..5989889d8 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -6,7 +6,7 @@ requires = [
     "cymem>=2.0.2,<2.1.0",
     "preshed>=3.0.2,<3.1.0",
     "murmurhash>=0.28.0,<1.1.0",
-    "thinc>=8.0.0a19,<8.0.0a30",
+    "thinc>=8.0.0a21,<8.0.0a30",
     "blis>=0.4.0,<0.5.0",
     "pytokenizations",
     "smart_open>=2.0.0,<3.0.0"
diff --git a/requirements.txt b/requirements.txt
index d0413825b..ee892b393 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,7 +1,7 @@
 # Our libraries
 cymem>=2.0.2,<2.1.0
 preshed>=3.0.2,<3.1.0
-thinc>=8.0.0a19,<8.0.0a30
+thinc>=8.0.0a21,<8.0.0a30
 blis>=0.4.0,<0.5.0
 ml_datasets>=0.1.1
 murmurhash>=0.28.0,<1.1.0
diff --git a/setup.cfg b/setup.cfg
index d2cb7c92a..f8f4561bf 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -34,13 +34,13 @@ setup_requires =
     cymem>=2.0.2,<2.1.0
     preshed>=3.0.2,<3.1.0
     murmurhash>=0.28.0,<1.1.0
-    thinc>=8.0.0a19,<8.0.0a30
+    thinc>=8.0.0a21,<8.0.0a30
 install_requires =
     # Our libraries
     murmurhash>=0.28.0,<1.1.0
     cymem>=2.0.2,<2.1.0
     preshed>=3.0.2,<3.1.0
-    thinc>=8.0.0a19,<8.0.0a30
+    thinc>=8.0.0a21,<8.0.0a30
     blis>=0.4.0,<0.5.0
     wasabi>=0.7.1,<1.1.0
     srsly>=2.1.0,<3.0.0
diff --git a/spacy/cli/debug_model.py b/spacy/cli/debug_model.py
index 0aea38e5c..8c0726cc3 100644
--- a/spacy/cli/debug_model.py
+++ b/spacy/cli/debug_model.py
@@ -2,7 +2,7 @@ from typing import Dict, Any, Optional
 from pathlib import Path
 from wasabi import msg
 from thinc.api import require_gpu, fix_random_seed, set_dropout_rate, Adam, Config
-from thinc.api import Model
+from thinc.api import Model, DATA_VALIDATION
 import typer
 
 from ._util import Arg, Opt, debug_cli, show_validation_error, parse_config_overrides
@@ -90,7 +90,9 @@ def debug_model(model: Model, *, print_settings: Optional[Dict[str, Any]] = None
     # STEP 1: Initializing the model and printing again
     Y = _get_output(model.ops.xp)
     _set_output_dim(nO=Y.shape[-1], model=model)
+    DATA_VALIDATION.set(False)   # The output vector might differ from the official type of the output layer
     model.initialize(X=_get_docs(), Y=Y)
+    DATA_VALIDATION.set(True)
     if print_settings.get("print_after_init"):
         msg.info(f"After initialization:")
         _print_model(model, print_settings)