diff --git a/CHANGELOG.md b/CHANGELOG.md
index d9fe32c1..3ff03501 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,7 +2,7 @@
 
 All notable changes to this project will be documented in this file. This project adheres to [Semantic Versioning](http://semver.org/).
 
-## [0.5.1] - 2024-01-xx
+## [0.5.1] - 2024-01-02
 
 ## Added
 - SMTP smuggling protection: Sanitization of outgoing messages that do not use `CRLF` as line endings.
@@ -13,8 +13,9 @@ All notable changes to this project will be documented in this file. This projec
 ### Fixed
 - Invalid DKIM signatures for empty message bodies.
 - IMAP command `SEARCH BEFORE` is not properly parsed.
-- IMAP response to `ENABLE` command misses enabled capabilities list.
+- IMAP command `FETCH` fails to parse single arguments without parentheses.
 - IMAP command `ENABLE QRESYNC` should also enable `CONDSTORE` extension.
+- IMAP response to `ENABLE` command does not include enabled capabilities list.
 - IMAP response to `FETCH ENVELOPE` should not return `NIL` when the `From` header is missing.
 
 ## [0.5.0] - 2023-12-27
diff --git a/Cargo.lock b/Cargo.lock
index 7eddb06c..9901a578 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2545,7 +2545,7 @@ checksum = "029d73f573d8e8d63e6d5020011d3255b28c3ba85d6cf870a07184ed23de9284"
 
 [[package]]
 name = "imap"
-version = "0.5.0"
+version = "0.5.1"
 dependencies = [
  "ahash 0.8.7",
  "dashmap",
@@ -2722,7 +2722,7 @@ dependencies = [
 
 [[package]]
 name = "jmap"
-version = "0.5.0"
+version = "0.5.1"
 dependencies = [
  "aes",
  "aes-gcm",
@@ -3132,7 +3132,7 @@ dependencies = [
 
 [[package]]
 name = "mail-server"
-version = "0.5.0"
+version = "0.5.1"
 dependencies = [
  "directory",
  "imap",
@@ -3149,7 +3149,7 @@ dependencies = [
 
 [[package]]
 name = "managesieve"
-version = "0.5.0"
+version = "0.5.1"
 dependencies = [
  "ahash 0.8.7",
  "bincode",
@@ -3416,7 +3416,7 @@ dependencies = [
 
 [[package]]
 name = "nlp"
-version = "0.5.0"
+version = "0.5.1"
 dependencies = [
  "ahash 0.8.7",
  "bincode",
@@ -5357,7 +5357,7 @@ checksum = "4dccd0940a2dcdf68d092b8cbab7dc0ad8fa938bf95787e1b916b0e3d0e8e970"
 
 [[package]]
 name = "smtp"
-version = "0.5.0"
+version = "0.5.1"
 dependencies = [
  "ahash 0.8.7",
  "bincode",
@@ -5479,7 +5479,7 @@ dependencies = [
 
 [[package]]
 name = "stalwart-cli"
-version = "0.5.0"
+version = "0.5.1"
 dependencies = [
  "clap",
  "console",
@@ -5503,7 +5503,7 @@ dependencies = [
 
 [[package]]
 name = "stalwart-install"
-version = "0.5.0"
+version = "0.5.1"
 dependencies = [
  "base64 0.21.5",
  "clap",
@@ -6385,7 +6385,7 @@ checksum = "711b9620af191e0cdc7468a8d14e709c3dcdb115b36f838e601583af800a370a"
 
 [[package]]
 name = "utils"
-version = "0.5.0"
+version = "0.5.1"
 dependencies = [
  "ahash 0.8.7",
  "chrono",
diff --git a/crates/cli/Cargo.toml b/crates/cli/Cargo.toml
index ff3d3089..12963d47 100644
--- a/crates/cli/Cargo.toml
+++ b/crates/cli/Cargo.toml
@@ -5,7 +5,7 @@ authors = ["Stalwart Labs Ltd. <hello@stalw.art>"]
 license = "AGPL-3.0-only"
 repository = "https://github.com/stalwartlabs/cli"
 homepage = "https://github.com/stalwartlabs/cli"
-version = "0.5.0"
+version = "0.5.1"
 edition = "2021"
 readme = "README.md"
 resolver = "2"
diff --git a/crates/imap-proto/src/parser/fetch.rs b/crates/imap-proto/src/parser/fetch.rs
index 35c65eed..2e43be16 100644
--- a/crates/imap-proto/src/parser/fetch.rs
+++ b/crates/imap-proto/src/parser/fetch.rs
@@ -343,6 +343,10 @@ impl Request<Command> {
                         )
                             .into());
                     }
+
+                    if !in_parentheses {
+                        break;
+                    }
                 }
                 Token::ParenthesisOpen => {
                     if !in_parentheses {
@@ -778,6 +782,16 @@ mod tests {
                     include_vanished: true,
                 },
             ),
+            (
+                "9 UID FETCH 1:* UID (VANISHED CHANGEDSINCE 1)\r\n",
+                fetch::Arguments {
+                    tag: "9".to_string(),
+                    sequence_set: Sequence::range(1.into(), None),
+                    attributes: vec![Attribute::Uid],
+                    changed_since: 1.into(),
+                    include_vanished: true,
+                },
+            ),
         ] {
             assert_eq!(
                 receiver
diff --git a/crates/imap-proto/src/protocol/fetch.rs b/crates/imap-proto/src/protocol/fetch.rs
index 48884784..61f2930d 100644
--- a/crates/imap-proto/src/protocol/fetch.rs
+++ b/crates/imap-proto/src/protocol/fetch.rs
@@ -1300,7 +1300,7 @@ mod tests {
                 concat!(
                     "BODYSTRUCTURE (((\"text\" \"PLAIN\" (\"CHARSET\" \"UTF-8\") ",
                     "\"<111@domain.com>\" \"Text part\" \"7BIT\" 1152 23 \"8o3456\" ",
-                    "(\"inline\" ()) \"en-US\" \"right here\")",
+                    "(\"inline\" NIL) \"en-US\" \"right here\")",
                     "(\"text\" \"HTML\" (\"CHARSET\" \"UTF-8\") ",
                     "\"<54535@domain.com>\" \"HTML part\" \"8BIT\" 45345 994 \"53454\" ",
                     "(\"attachment\" (\"filename\" \"myfile.txt\")) ",
diff --git a/crates/imap/Cargo.toml b/crates/imap/Cargo.toml
index 413a9a6b..f13cdb9e 100644
--- a/crates/imap/Cargo.toml
+++ b/crates/imap/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "imap"
-version = "0.5.0"
+version = "0.5.1"
 edition = "2021"
 resolver = "2"
 
diff --git a/crates/install/Cargo.toml b/crates/install/Cargo.toml
index 22f79a8f..d3eec77c 100644
--- a/crates/install/Cargo.toml
+++ b/crates/install/Cargo.toml
@@ -5,7 +5,7 @@ authors = ["Stalwart Labs Ltd. <hello@stalw.art>"]
 license = "AGPL-3.0-only"
 repository = "https://github.com/stalwartlabs/mail-server"
 homepage = "https://github.com/stalwartlabs/mail-server"
-version = "0.5.0"
+version = "0.5.1"
 edition = "2021"
 readme = "README.md"
 resolver = "2"
diff --git a/crates/jmap/Cargo.toml b/crates/jmap/Cargo.toml
index 1ea025a6..b6b71f94 100644
--- a/crates/jmap/Cargo.toml
+++ b/crates/jmap/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "jmap"
-version = "0.5.0"
+version = "0.5.1"
 edition = "2021"
 resolver = "2"
 
diff --git a/crates/main/Cargo.toml b/crates/main/Cargo.toml
index 4006565a..90976ec4 100644
--- a/crates/main/Cargo.toml
+++ b/crates/main/Cargo.toml
@@ -7,7 +7,7 @@ homepage = "https://stalw.art"
 keywords = ["imap", "jmap", "smtp", "email", "mail", "server"]
 categories = ["email"]
 license = "AGPL-3.0-only"
-version = "0.5.0"
+version = "0.5.1"
 edition = "2021"
 resolver = "2"
 
diff --git a/crates/managesieve/Cargo.toml b/crates/managesieve/Cargo.toml
index 74cb0465..ba51fff4 100644
--- a/crates/managesieve/Cargo.toml
+++ b/crates/managesieve/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "managesieve"
-version = "0.5.0"
+version = "0.5.1"
 edition = "2021"
 resolver = "2"
 
diff --git a/crates/nlp/Cargo.toml b/crates/nlp/Cargo.toml
index 3d70992f..8f72759f 100644
--- a/crates/nlp/Cargo.toml
+++ b/crates/nlp/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "nlp"
-version = "0.5.0"
+version = "0.5.1"
 edition = "2021"
 resolver = "2"
 
diff --git a/crates/smtp/Cargo.toml b/crates/smtp/Cargo.toml
index be0331c4..f807291d 100644
--- a/crates/smtp/Cargo.toml
+++ b/crates/smtp/Cargo.toml
@@ -7,7 +7,7 @@ homepage = "https://stalw.art/smtp"
 keywords = ["smtp", "email", "mail", "server"]
 categories = ["email"]
 license = "AGPL-3.0-only"
-version = "0.5.0"
+version = "0.5.1"
 edition = "2021"
 resolver = "2"
 
diff --git a/crates/utils/Cargo.toml b/crates/utils/Cargo.toml
index 881ff990..f30dad05 100644
--- a/crates/utils/Cargo.toml
+++ b/crates/utils/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "utils"
-version = "0.5.0"
+version = "0.5.1"
 edition = "2021"
 resolver = "2"
 
diff --git a/tests/resources/scripts/create_test_users.sh b/tests/resources/scripts/create_test_users.sh
index 5e0f295c..84979ce9 100644
--- a/tests/resources/scripts/create_test_users.sh
+++ b/tests/resources/scripts/create_test_users.sh
@@ -13,4 +13,4 @@ cargo run -p stalwart-cli -- -u https://127.0.0.1:8080 -c admin:secret account c
 #cargo run -p stalwart-cli -- -u https://127.0.0.1:8080 -c admin:secret list add-members everyone jane john bill
 #cargo run -p stalwart-cli -- -u https://127.0.0.1:8080 -c admin:secret account list
 #cargo run -p stalwart-cli -- -u https://127.0.0.1:8080 -c admin:secret import messages --format mbox john _ignore/dovecot-crlf 
-
+#cargo run -p stalwart-cli -- -u https://127.0.0.1:8080 -c admin:secret import messages --format maildir john /var/mail/john
diff --git a/tests/resources/scripts/imap_import_single.py b/tests/resources/scripts/imap_import_single.py
new file mode 100644
index 00000000..e45c5982
--- /dev/null
+++ b/tests/resources/scripts/imap_import_single.py
@@ -0,0 +1,27 @@
+import imaplib
+import socket
+import time
+from email.message import Message
+from email.utils import formatdate
+from datetime import datetime, timedelta
+
+conn = imaplib.IMAP4('localhost')
+conn.login('john', '12345')
+conn.socket().setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
+current_date = datetime.now()
+timestamp = current_date.timestamp()
+
+msg = Message()
+msg['From'] = 'somebody@some.where'
+msg['To'] = 'john@example.org'
+msg['Message-Id'] = f'unique.message.id.{current_date}@nowhere'
+msg['Date'] = formatdate(time.mktime(current_date.timetuple()), localtime=False, usegmt=True)
+msg['Subject'] = f"This is message #{timestamp}"
+msg.set_payload('...nothing...')
+
+response_code, response_details = conn.append('INBOX', '', imaplib.Time2Internaldate(time.mktime(current_date.timetuple())), str(msg).encode('utf-8'))
+if response_code != 'OK':
+    print(f'Error while appending message: {response_code} {response_details}')
+
+print("Message appended.")
+conn.logout()