Merge remote-tracking branch 'origin/develop' into pr5389-merge

# Conflicts:
#	.github/workflows/ubuntu.yml
#	cmake/ci.cmake

single_include/nlohmann/json.hpp

@@ -20384,6 +20384,16 @@ class binary_writer
         };
 
         string_t key = "_ArrayType_";
+        // the type name is looked up as a string below; a non-string
+        // annotation (e.g. a number, null, or an array) cannot name a known
+        // dtype, so it is treated the same as an unrecognized type name and
+        // falls back to a plain object encoding instead of throwing
+        // type_error.302 out of get<string_t>()
+        if (!value.at(key).is_string())
+        {
+            return true;
+        }
+
         // use get<string_t>() instead of static_cast<string_t> to avoid an
         // ambiguous conversion under explicit instantiation on C++17 (see #4825)
         auto it = bjdtype.find(value.at(key).template get<string_t>());
@@ -20393,6 +20403,16 @@ class binary_writer
         }
         CharType dtype = it->second;
 
+        // the 'B' (byte) marker is only defined from BJData Draft 3 onward;
+        // emitting it under an earlier draft would produce a stream that an
+        // earlier-draft reader rejects, so such an object falls back to a
+        // plain object encoding instead (see the "Binary values" section of
+        // the BJData documentation)
+        if (dtype == 'B' && bjdata_version < bjdata_version_t::draft3)
+        {
+            return true;
+        }
+
         key = "_ArraySize_";
         // the dimensions are written verbatim as the header length below, so a
         // value that is not an array cannot produce a valid one: null emits 'Z'