diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -3242,6 +3242,10 @@
   LangOpts.CPlusPlus17 = LexingStd >= FormatStyle::LS_Cpp17;
   LangOpts.CPlusPlus20 = LexingStd >= FormatStyle::LS_Cpp20;
   LangOpts.Char8 = LexingStd >= FormatStyle::LS_Cpp20;
+  // Turning on digraphs in standards before C++0x is error-prone, because e.g.
+  // the sequence "<::" will be unconditionally treated as "[:".
+  // Cf. Lexer::LexTokenInternal.
+  LangOpts.Digraphs = LexingStd >= FormatStyle::LS_Cpp11;
 
   LangOpts.LineComment = 1;
   bool AlternativeOperators = Style.isCpp();
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -24219,6 +24219,16 @@
                Style);
 }
 
+TEST_F(FormatTest, UnderstandsDigraphs) {
+  verifyFormat("int arr<:5:> = {};");
+  verifyFormat("int arr[5] = <%%>;");
+  verifyFormat("int arr<:::qualified_variable:> = {};");
+  verifyFormat("int arr[::qualified_variable] = <%%>;");
+  verifyFormat("%:include <header>");
+  verifyFormat("%:define A x##y");
+  verifyFormat("#define A x%:%:y");
+}
+
 } // namespace
 } // namespace format
 } // namespace clang