diff --git a/Source/.clang-tidy b/Source/.clang-tidy
index c85dc18e2..fadf1c637 100644
--- a/Source/.clang-tidy
+++ b/Source/.clang-tidy
@@ -30,6 +30,9 @@
 #
 # -modernize-use-trailing-return-type
 #   A purely stylistic change that we do not want.
+#
+# -modernize-concat-nested-namespaces
+#   Compatibility with older compilers.
 Checks: >
   -*,
   bugprone-*,
@@ -44,6 +47,7 @@ Checks: >
   readability-*,
   -modernize-avoid-c-arrays,
   -modernize-use-trailing-return-type,
+  -modernize-concat-nested-namespaces
 
 HeaderFilterRegex: "^(Source|test)\\.h$"
 
diff --git a/Source/dvlnet/abstract_net.cpp b/Source/dvlnet/abstract_net.cpp
index 72be2b237..f3827fe49 100644
--- a/Source/dvlnet/abstract_net.cpp
+++ b/Source/dvlnet/abstract_net.cpp
@@ -10,7 +10,8 @@
 #include "dvlnet/loopback.h"
 #include "storm/storm.h"
 
-namespace devilution::net {
+namespace devilution {
+namespace net {
 
 std::unique_ptr<abstract_net> abstract_net::make_net(provider_t provider)
 {
@@ -30,4 +31,5 @@ std::unique_ptr<abstract_net> abstract_net::make_net(provider_t provider)
 #endif
 }
 
-} // namespace devilution::net
+} // namespace net
+} // namespace devilution
diff --git a/Source/dvlnet/base.cpp b/Source/dvlnet/base.cpp
index 064c6907a..af8a07529 100644
--- a/Source/dvlnet/base.cpp
+++ b/Source/dvlnet/base.cpp
@@ -4,7 +4,8 @@
 #include <cstring>
 #include <memory>
 
-namespace devilution::net {
+namespace devilution {
+namespace net {
 
 void base::setup_gameinfo(buffer_t info)
 {
@@ -262,4 +263,5 @@ bool base::SNetGetTurnsInTransit(DWORD *turns)
 	return true;
 }
 
-} // namespace devilution::net
+} // namespace net
+} // namespace devilution
diff --git a/Source/dvlnet/frame_queue.cpp b/Source/dvlnet/frame_queue.cpp
index 25b64a63f..525ae89a3 100644
--- a/Source/dvlnet/frame_queue.cpp
+++ b/Source/dvlnet/frame_queue.cpp
@@ -4,7 +4,8 @@
 
 #include "dvlnet/packet.h"
 
-namespace devilution::net {
+namespace devilution {
+namespace net {
 
 framesize_t frame_queue::size()
 {
@@ -77,4 +78,5 @@ buffer_t frame_queue::make_frame(buffer_t packetbuf)
 	return ret;
 }
 
-} // namespace devilution::net
+} // namespace net
+} // namespace devilution
diff --git a/Source/dvlnet/loopback.cpp b/Source/dvlnet/loopback.cpp
index ff732eb5b..cdc503dd2 100644
--- a/Source/dvlnet/loopback.cpp
+++ b/Source/dvlnet/loopback.cpp
@@ -2,7 +2,8 @@
 #include "utils/stubs.h"
 #include "utils/language.h"
 
-namespace devilution::net {
+namespace devilution {
+namespace net {
 
 int loopback::create(std::string addrstr, std::string passwd)
 {
@@ -112,4 +113,5 @@ std::string loopback::make_default_gamename()
 	return std::string(_("loopback"));
 }
 
-} // namespace devilution::net
+} // namespace net
+} // namespace devilution
diff --git a/Source/dvlnet/packet.cpp b/Source/dvlnet/packet.cpp
index ba7393258..37d2cb37d 100644
--- a/Source/dvlnet/packet.cpp
+++ b/Source/dvlnet/packet.cpp
@@ -1,6 +1,7 @@
 #include "dvlnet/packet.h"
 
-namespace devilution::net {
+namespace devilution {
+namespace net {
 
 #ifndef NONET
 static constexpr bool DisableEncryption = false;
@@ -233,4 +234,5 @@ packet_factory::packet_factory(std::string pw)
 #endif
 }
 
-} // namespace devilution::net
+} // namespace net
+} // namespace devilution
diff --git a/Source/dvlnet/protocol_zt.cpp b/Source/dvlnet/protocol_zt.cpp
index 21dbcd9ad..8ea0f004b 100644
--- a/Source/dvlnet/protocol_zt.cpp
+++ b/Source/dvlnet/protocol_zt.cpp
@@ -18,7 +18,8 @@
 #include "dvlnet/zerotier_native.h"
 #include "utils/log.hpp"
 
-namespace devilution::net {
+namespace devilution {
+namespace net {
 
 protocol_zt::protocol_zt()
 {
@@ -305,4 +306,5 @@ std::string protocol_zt::make_default_gamename()
 	return ret;
 }
 
-} // namespace devilution::net
+} // namespace net
+} // namespace devilution
diff --git a/Source/dvlnet/tcp_client.cpp b/Source/dvlnet/tcp_client.cpp
index bda51d788..d5b0fd6f0 100644
--- a/Source/dvlnet/tcp_client.cpp
+++ b/Source/dvlnet/tcp_client.cpp
@@ -13,7 +13,8 @@
 
 #include <asio/connect.hpp>
 
-namespace devilution::net {
+namespace devilution {
+namespace net {
 
 int tcp_client::create(std::string addrstr, std::string passwd)
 {
@@ -137,4 +138,5 @@ tcp_client::~tcp_client()
 {
 }
 
-} // namespace devilution::net
+} // namespace net
+} // namespace devilution
diff --git a/Source/dvlnet/tcp_server.cpp b/Source/dvlnet/tcp_server.cpp
index 7fe675ab1..3a233b1b1 100644
--- a/Source/dvlnet/tcp_server.cpp
+++ b/Source/dvlnet/tcp_server.cpp
@@ -8,7 +8,8 @@
 #include "dvlnet/base.h"
 #include "utils/log.hpp"
 
-namespace devilution::net {
+namespace devilution {
+namespace net {
 
 tcp_server::tcp_server(asio::io_context &ioc, const std::string &bindaddr,
     unsigned short port, std::string pw)
@@ -225,4 +226,5 @@ tcp_server::~tcp_server()
 {
 }
 
-} // namespace devilution::net
+} // namespace net
+} // namespace devilution
diff --git a/Source/dvlnet/zerotier_lwip.cpp b/Source/dvlnet/zerotier_lwip.cpp
index e2737e16b..6d37d6ae3 100644
--- a/Source/dvlnet/zerotier_lwip.cpp
+++ b/Source/dvlnet/zerotier_lwip.cpp
@@ -17,7 +17,8 @@
 
 #include "dvlnet/zerotier_native.h"
 
-namespace devilution::net {
+namespace devilution {
+namespace net {
 
 void print_ip6_addr(void *x)
 {
@@ -37,4 +38,5 @@ void zt_ip6setup()
 	UNLOCK_TCPIP_CORE();
 }
 
-} // namespace devilution::net
+} // namespace net
+} // namespace devilution
diff --git a/Source/dvlnet/zerotier_native.cpp b/Source/dvlnet/zerotier_native.cpp
index b4763c7d5..66a8001b0 100644
--- a/Source/dvlnet/zerotier_native.cpp
+++ b/Source/dvlnet/zerotier_native.cpp
@@ -17,7 +17,8 @@
 
 #include "dvlnet/zerotier_lwip.h"
 
-namespace devilution::net {
+namespace devilution {
+namespace net {
 
 //static constexpr uint64_t zt_earth = 0x8056c2e21c000001;
 static constexpr uint64_t ZtNetwork = 0xaf78bf943649eb12;
@@ -67,4 +68,5 @@ void zerotier_network_start()
 	std::atexit(zerotier_network_stop);
 }
 
-} // namespace devilution::net
+} // namespace net
+} // namespace devilution
diff --git a/Source/utils/paths.cpp b/Source/utils/paths.cpp
index 6ed7c78eb..d6530aade 100644
--- a/Source/utils/paths.cpp
+++ b/Source/utils/paths.cpp
@@ -88,21 +88,21 @@ const std::string &ConfigPath()
 const std::string &LangPath()
 {
 	if (!langPath)
-		langPath = MO_LANG_DIR;
+		langPath.emplace(MO_LANG_DIR);
 	return *langPath;
 }
 
 const std::string &TtfPath()
 {
 	if (!ttfPath)
-		ttfPath = TTF_FONT_DIR;
+		ttfPath.emplace(TTF_FONT_DIR);
 	return *ttfPath;
 }
 
 const std::string &TtfName()
 {
 	if (!ttfName)
-		ttfName = TTF_FONT_NAME;
+		ttfName.emplace(TTF_FONT_NAME);
 	return *ttfName;
 }
 
diff --git a/Source/utils/push_aulib_decoder.cpp b/Source/utils/push_aulib_decoder.cpp
index 53dd9621c..34c3e99e0 100644
--- a/Source/utils/push_aulib_decoder.cpp
+++ b/Source/utils/push_aulib_decoder.cpp
@@ -36,7 +36,7 @@ void PushAulibDecoder::PushSamples(const std::uint8_t *data, unsigned size) noex
 void PushAulibDecoder::DiscardPendingSamples() noexcept
 {
 	SDLMutexLockGuard lock(queue_mutex_.get());
-	queue_ = {};
+	queue_ = std::queue<AudioQueueItem>();
 }
 
 bool PushAulibDecoder::open([[maybe_unused]] SDL_RWops *rwops)