diff --git a/wpimath/src/main/native/include/units/base.h b/wpimath/src/main/native/include/units/base.h
index 3c939f3..09c56e5 100644
--- a/wpimath/src/main/native/include/units/base.h
+++ b/wpimath/src/main/native/include/units/base.h
@@ -183,9 +183,10 @@ namespace units
 	struct fmt::formatter<units::namespaceName::nameSingular ## _t> \
 		: fmt::formatter<double> \
 	{\
-		template <typename FormatContext>\
-		auto format(const units::namespaceName::nameSingular ## _t& obj,\
-								FormatContext& ctx) -> decltype(ctx.out()) \
+		template <typename FmtContext>\
+		auto format(\
+				const units::namespaceName::nameSingular ## _t& obj,\
+				FmtContext& ctx) const\
 		{\
 			auto out = ctx.out();\
 			out = fmt::formatter<double>::format(obj(), ctx);\
@@ -2890,9 +2891,10 @@ namespace units
 template <>
 struct fmt::formatter<units::dimensionless::dB_t> : fmt::formatter<double>
 {
-	template <typename FormatContext>
-	auto format(const units::dimensionless::dB_t& obj,
-							FormatContext& ctx) -> decltype(ctx.out())
+	template <typename FmtContext>
+	auto format(
+			const units::dimensionless::dB_t& obj,
+			FmtContext& ctx) const
 	{
 		auto out = ctx.out();
 		out = fmt::formatter<double>::format(obj(), ctx);