diff --git a/util.cpp b/util.cpp
index e871dac1..bd77e682 100644
--- a/util.cpp
+++ b/util.cpp
@@ -81,7 +81,7 @@ namespace http
 				if (colon != std::string::npos)
 				{
 					std::string field = header.substr (0, colon);
-					boost::to_lower (field);
+					std::transform(field.begin(), field.end(), field.begin(), ::tolower);
 					if (field == i2p::util::http::TRANSFER_ENCODING)
 						isChunked = (header.find ("chunked", colon + 1) != std::string::npos);
 				}