diff --git a/AGHTechDoc.md b/AGHTechDoc.md
index c1b53300..42c15a46 100644
--- a/AGHTechDoc.md
+++ b/AGHTechDoc.md
@@ -835,7 +835,7 @@ Request:
 Response:
 
 	200 OK
-	
+
 ### API: Validate TLS configuration
 
 Request:
@@ -2008,7 +2008,7 @@ Request:
 Response:
 
 	200 OK
-	
+
     DOH plist file
 
 ## API: Get DNS over TLS .mobileconfig
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6e6a537a..8d20d3e1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -69,9 +69,10 @@ In this release, the schema version has changed from 24 to 25.
 
 ### Fixed
 
+- Occasional DNS-over-QUIC and DNS-over-HTTP/3 errors ([#6133]).
 - Legacy DNS rewrites containing IPv4-mapped IPv6 addresses are now matching the
   `AAAA` requests, not `A` ([#6050]).
-- File log configuration, such as `max_size`, being ignored ([#6093]). 
+- File log configuration, such as `max_size`, being ignored ([#6093]).
 - Panic on using a single-slash filtering rule.
 - Panic on shutting down while DNS requests are in process of filtering
   ([#5948]).
@@ -84,6 +85,7 @@ In this release, the schema version has changed from 24 to 25.
 [#6053]: https://github.com/AdguardTeam/AdGuardHome/issues/6053
 [#6093]: https://github.com/AdguardTeam/AdGuardHome/issues/6093
 [#6122]: https://github.com/AdguardTeam/AdGuardHome/issues/6122
+[#6133]: https://github.com/AdguardTeam/AdGuardHome/issues/6133
 
 <!--
 NOTE: Add new changes ABOVE THIS COMMENT.
diff --git a/go.mod b/go.mod
index 014d8845..f97e0843 100644
--- a/go.mod
+++ b/go.mod
@@ -27,7 +27,7 @@ require (
 	// own code for that.  Perhaps, use gopacket.
 	github.com/mdlayher/raw v0.1.0
 	github.com/miekg/dns v1.1.55
-	github.com/quic-go/quic-go v0.37.4
+	github.com/quic-go/quic-go v0.38.0
 	github.com/stretchr/testify v1.8.4
 	github.com/ti-mo/netfilter v0.5.0
 	go.etcd.io/bbolt v1.3.7
@@ -48,7 +48,7 @@ require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/go-task/slim-sprig v0.0.0-20230315185526-52ccab3ef572 // indirect
 	github.com/golang/mock v1.6.0 // indirect
-	github.com/google/pprof v0.0.0-20230811205829-9131a7e9cc17 // indirect
+	github.com/google/pprof v0.0.0-20230821062121-407c9e7a662f // indirect
 	github.com/mdlayher/socket v0.4.1 // indirect
 	github.com/onsi/ginkgo/v2 v2.11.0 // indirect
 	github.com/patrickmn/go-cache v2.1.0+incompatible // indirect
@@ -56,7 +56,7 @@ require (
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/quic-go/qpack v0.4.0 // indirect
-	github.com/quic-go/qtls-go1-20 v0.3.2 // indirect
+	github.com/quic-go/qtls-go1-20 v0.3.3 // indirect
 	github.com/u-root/uio v0.0.0-20230305220412-3e8cd9d6bf63 // indirect
 	golang.org/x/mod v0.12.0 // indirect
 	golang.org/x/sync v0.3.0 // indirect
diff --git a/go.sum b/go.sum
index bf1c6e7f..431cdaca 100644
--- a/go.sum
+++ b/go.sum
@@ -43,8 +43,8 @@ github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
 github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/google/gopacket v1.1.19 h1:ves8RnFZPGiFnTS0uPQStjwru6uO6h+nlr9j6fL7kF8=
 github.com/google/gopacket v1.1.19/go.mod h1:iJ8V8n6KS+z2U1A8pUwu8bW5SyEMkXJB8Yo/Vo+TKTo=
-github.com/google/pprof v0.0.0-20230811205829-9131a7e9cc17 h1:0h35ESZ02+hN/MFZb7XZOXg+Rl9+Rk8fBIf5YLws9gA=
-github.com/google/pprof v0.0.0-20230811205829-9131a7e9cc17/go.mod h1:Jh3hGz2jkYak8qXPD19ryItVnUgpgeqzdkY/D0EaeuA=
+github.com/google/pprof v0.0.0-20230821062121-407c9e7a662f h1:pDhu5sgp8yJlEF/g6osliIIpF9K4F5jvkULXa4daRDQ=
+github.com/google/pprof v0.0.0-20230821062121-407c9e7a662f/go.mod h1:czg5+yv1E0ZGTi6S6vVK1mke0fV+FaUhNGcd6VRS9Ik=
 github.com/google/renameio/v2 v2.0.0 h1:UifI23ZTGY8Tt29JbYFiuyIU3eX+RNFtUwefq9qAhxg=
 github.com/google/renameio/v2 v2.0.0/go.mod h1:BtmJXm5YlszgC+TD4HOEEUFgkJP3nLxehU6hfe7jRt4=
 github.com/google/uuid v1.2.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
@@ -94,10 +94,10 @@ github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZN
 github.com/power-devops/perfstat v0.0.0-20210106213030-5aafc221ea8c h1:ncq/mPwQF4JjgDlrVEn3C11VoGHZN7m8qihwgMEtzYw=
 github.com/quic-go/qpack v0.4.0 h1:Cr9BXA1sQS2SmDUWjSofMPNKmvF6IiIfDRmgU0w1ZCo=
 github.com/quic-go/qpack v0.4.0/go.mod h1:UZVnYIfi5GRk+zI9UMaCPsmZ2xKJP7XBUvVyT1Knj9A=
-github.com/quic-go/qtls-go1-20 v0.3.2 h1:rRgN3WfnKbyik4dBV8A6girlJVxGand/d+jVKbQq5GI=
-github.com/quic-go/qtls-go1-20 v0.3.2/go.mod h1:X9Nh97ZL80Z+bX/gUXMbipO6OxdiDi58b/fMC9mAL+k=
-github.com/quic-go/quic-go v0.37.4 h1:ke8B73yMCWGq9MfrCCAw0Uzdm7GaViC3i39dsIdDlH4=
-github.com/quic-go/quic-go v0.37.4/go.mod h1:YsbH1r4mSHPJcLF4k4zruUkLBqctEMBDR6VPvcYjIsU=
+github.com/quic-go/qtls-go1-20 v0.3.3 h1:17/glZSLI9P9fDAeyCHBFSWSqJcwx1byhLwP5eUIDCM=
+github.com/quic-go/qtls-go1-20 v0.3.3/go.mod h1:X9Nh97ZL80Z+bX/gUXMbipO6OxdiDi58b/fMC9mAL+k=
+github.com/quic-go/quic-go v0.38.0 h1:T45lASr5q/TrVwt+jrVccmqHhPL2XuSyoCLVCpfOSLc=
+github.com/quic-go/quic-go v0.38.0/go.mod h1:MPCuRq7KBK2hNcfKj/1iD1BGuN3eAYMeNxp3T42LRUg=
 github.com/shirou/gopsutil/v3 v3.23.7 h1:C+fHO8hfIppoJ1WdsVm1RoI0RwXoNdfTK7yWXV0wVj4=
 github.com/shoenig/go-m1cpu v0.1.6 h1:nxdKQNcEB6vzgA2E2bvzKIYRuNj7XNJ4S/aRSwKzFtM=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
diff --git a/internal/dhcpd/README.md b/internal/dhcpd/README.md
index 5c692e04..8bb51147 100644
--- a/internal/dhcpd/README.md
+++ b/internal/dhcpd/README.md
@@ -16,17 +16,17 @@ To set up a test environment for DHCP server you will need:
 
    ### Configure Virtual Box
 
- 1.  Install Virtual Box and run the following command to create a Host-Only 
+ 1.  Install Virtual Box and run the following command to create a Host-Only
      network:
 
      ```sh
      $ VBoxManage hostonlyif create
      ```
-     
-     You can check its status by `ip a` command.  
 
-     You can also set up Host-Only network using Virtual Box menu: 
-     
+     You can check its status by `ip a` command.
+
+     You can also set up Host-Only network using Virtual Box menu:
+
      ```
      File -> Host Network Manager...
      ```
diff --git a/openapi/CHANGELOG.md b/openapi/CHANGELOG.md
index 64495ca5..fe35e4c9 100644
--- a/openapi/CHANGELOG.md
+++ b/openapi/CHANGELOG.md
@@ -29,8 +29,14 @@
 
 ```json
 {
-  "target": {"domain":"example.com","answer":"answer-to-update"},
-  "update": {"domain":"example.com","answer":"new-answer"}
+  "target": {
+    "domain": "example.com",
+    "answer": "answer-to-update"
+  },
+  "update": {
+    "domain": "example.com",
+    "answer": "new-answer"
+  }
 }
 ```
 
@@ -88,7 +94,9 @@ return a JSON object with the following format:
 {
   "enabled": true,
   "interval": 3600,
-  "ignored": ["example.com"],
+  "ignored": [
+    "example.com"
+  ]
 }
 ```
 
@@ -119,7 +127,9 @@ accept and return a JSON object with the following format:
   "enabled": true,
   "anonymize_client_ip": false,
   "interval": 3600,
-  "ignored": ["example.com"],
+  "ignored": [
+    "example.com"
+  ]
 }
 ```
 
@@ -251,7 +261,7 @@ JSON object with the following format:
 
 ```json
 {
-  "name":"user name", 
+  "name": "user name",
   "language": "en",
   "theme": "auto"
 }
@@ -327,8 +337,7 @@ the filters must be presented in a JSON object with the following format:
 
 ```json
 {
-  "rules":
-  [
+  "rules": [
     "||example.com^",
     "# comment",
     "@@||www.example.com^"
diff --git a/scripts/install.sh b/scripts/install.sh
index 8c30268d..08c54e87 100644
--- a/scripts/install.sh
+++ b/scripts/install.sh
@@ -468,7 +468,7 @@ rerun_with_root() {
 	readonly r u v
 
 	log 'restarting with root privileges'
-	
+
 	# Group curl/wget together with an echo, so that if the former fails before
 	# producing any output, the latter prints an exit command for the following
 	# shell to execute to prevent it from getting an empty input and exiting
diff --git a/scripts/make/txt-lint.sh b/scripts/make/txt-lint.sh
index 06273185..74d5758d 100644
--- a/scripts/make/txt-lint.sh
+++ b/scripts/make/txt-lint.sh
@@ -3,7 +3,7 @@
 # This comment is used to simplify checking local copies of the script.  Bump
 # this number every time a remarkable change is made to this script.
 #
-# AdGuard-Project-Version: 3
+# AdGuard-Project-Version: 4
 
 verbose="${VERBOSE:-0}"
 readonly verbose
@@ -49,8 +49,31 @@ trailing_newlines() {
 		done
 }
 
+# trailing_whitespace is a simple check that makes sure that there are no
+# trailing whitespace in plain-text files.
+trailing_whitespace() {
+	# NOTE: Adjust for your project.
+	git ls-files\
+		':!*.bmp'\
+		':!*.jpg'\
+		':!*.mmdb'\
+		':!*.png'\
+		':!*.svg'\
+		':!*.tar.gz'\
+		':!*.webp'\
+		':!*.zip'\
+		| while read -r f
+		do
+			grep -e '[[:space:]]$' -n -- "$f"\
+				| sed -e "s:^:${f}\::" -e 's/ \+$/>>>&<<</'
+		done
+}
+
 run_linter -e trailing_newlines
 
-git ls-files -- '*.md' '*.txt' '*.yaml' '*.yml' 'client/src/__locales/en.json'\
+run_linter -e trailing_whitespace
+
+git ls-files -- '*.conf' '*.md' '*.txt' '*.yaml' '*.yml'\
+	'client/src/__locales/en.json'\
 	| xargs misspell --error\
 	| sed -e 's/^/misspell: /'