diff --git a/CHANGELOG.md b/CHANGELOG.md
index 77b7eeb4c..346690f46 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,12 +11,17 @@ Notable changes between versions.
 - For full release notes, see:
   <https://github.com/PyThaiNLP/pythainlp/releases>
 - For detailed commit changes, see:
-  <https://github.com/PyThaiNLP/pythainlp/compare/v5.1.0...dev> (select tags to compare)
+  <https://github.com/PyThaiNLP/pythainlp/compare/v5.1.1...dev> (select tags to compare)
 
-## Version 5.1.0 -> Dev
+## Version 5.1.1 -> Dev
 
 [WIP]
 
+## Version 5.1.0 -> 5.1.1
+
+- PR Description: Refactor thai_consonants_all to Use set in syllable.py #1087
+- ThaiTransliterator: Select 1D CPU int64 tensor device #1089
+
 ## Version 5.0.5 -> 5.1.0
 
 - Add Thai Discourse Treebank postag #910
diff --git a/CITATION.cff b/CITATION.cff
index aa34b65a1..58a55563f 100644
--- a/CITATION.cff
+++ b/CITATION.cff
@@ -45,5 +45,5 @@ keywords:
   - "Thai language"
   - "Thai NLP"
 license: Apache-2.0
-version: 5.1.0
-date-released: "2025-02-25"
+version: 5.1.1
+date-released: "2025-03-31"
diff --git a/README.md b/README.md
index 028461e44..cebd95f59 100644
--- a/README.md
+++ b/README.md
@@ -30,7 +30,7 @@ pip install pythainlp
 
 | Version | Description | Status |
 |:------:|:--:|:------:|
-| [5.1.0](https://github.com/PyThaiNLP/pythainlp/releases) | Stable | [Change Log](https://github.com/PyThaiNLP/pythainlp/issues/900) |
+| [5.1.1](https://github.com/PyThaiNLP/pythainlp/releases) | Stable | [Change Log](https://github.com/PyThaiNLP/pythainlp/issues/900) |
 | [`dev`](https://github.com/PyThaiNLP/pythainlp/tree/dev) | Release Candidate for 5.2 | [Change Log](https://github.com/PyThaiNLP/pythainlp/issues/1080) |
 
 ## Getting Started
diff --git a/README_TH.md b/README_TH.md
index bb0b2e5cc..0e155a549 100644
--- a/README_TH.md
+++ b/README_TH.md
@@ -26,7 +26,7 @@ pip install pythainlp
 
 | รุ่น | คำอธิบาย | สถานะ |
 |:------:|:--:|:------:|
-| [5.1.0](https://github.com/PyThaiNLP/pythainlp/releases) | Stable | [Change Log](https://github.com/PyThaiNLP/pythainlp/issues/900) |
+| [5.1.1](https://github.com/PyThaiNLP/pythainlp/releases) | Stable | [Change Log](https://github.com/PyThaiNLP/pythainlp/issues/900) |
 | [`dev`](https://github.com/PyThaiNLP/pythainlp/tree/dev) | Release Candidate for 5.2  | [Change Log](https://github.com/PyThaiNLP/pythainlp/issues/1080) |
 
 ติดตามพวกเราบน [PyThaiNLP Facebook page](https://www.facebook.com/pythainlp/) เพื่อรับข่าวสารเพิ่มเติม
diff --git a/codemeta.json b/codemeta.json
index 7df85191a..f27f9bd22 100644
--- a/codemeta.json
+++ b/codemeta.json
@@ -3,7 +3,7 @@
   "@type": "SoftwareSourceCode",
   "name": "PyThaiNLP",
   "description": "Thai Natural Language Processing in Python",
-  "version": "5.1.0",
+  "version": "5.1.1",
   "author": [
     {
       "@type": "Person",
diff --git a/pythainlp/__init__.py b/pythainlp/__init__.py
index b32052002..808f3fd2d 100644
--- a/pythainlp/__init__.py
+++ b/pythainlp/__init__.py
@@ -2,7 +2,7 @@
 # SPDX-FileCopyrightText: 2016-2025 PyThaiNLP Project
 # SPDX-FileType: SOURCE
 # SPDX-License-Identifier: Apache-2.0
-__version__ = "5.1.0"
+__version__ = "5.1.1"
 
 thai_consonants = "กขฃคฅฆงจฉชซฌญฎฏฐฑฒณดตถทธนบปผฝพฟภมยรลวศษสหฬอฮ"  # 44 chars
 
diff --git a/pythainlp/transliterate/thai2rom.py b/pythainlp/transliterate/thai2rom.py
index fd27a3f7d..5341fb889 100644
--- a/pythainlp/transliterate/thai2rom.py
+++ b/pythainlp/transliterate/thai2rom.py
@@ -130,7 +130,7 @@ def forward(self, sequences, sequences_lengths):
 
         sequences_lengths = torch.flip(
             torch.sort(sequences_lengths).values, dims=(0,)
-        )
+        ).to(device)
         index_sorted = torch.sort(-1 * sequences_lengths).indices
         index_unsort = torch.sort(index_sorted).indices  # to unsorted sequence
         sequences = sequences.index_select(0, index_sorted.to(device))
@@ -139,7 +139,7 @@ def forward(self, sequences, sequences_lengths):
         sequences = self.dropout(sequences)
 
         sequences_packed = nn.utils.rnn.pack_padded_sequence(
-            sequences, sequences_lengths.clone(), batch_first=True
+            sequences, sequences_lengths.clone().to("cpu", torch.int64), batch_first=True
         )
 
         sequences_output, hidden = self.rnn(sequences_packed, hidden)
diff --git a/pythainlp/util/syllable.py b/pythainlp/util/syllable.py
index c8e5fb272..e91812e11 100644
--- a/pythainlp/util/syllable.py
+++ b/pythainlp/util/syllable.py
@@ -21,7 +21,7 @@
     "กบ": list("บปภพฟ"),
 }
 
-thai_consonants_all = list(thai_consonants)
+thai_consonants_all = set(thai_consonants)
 thai_consonants_all.remove("อ")
 
 _temp = list("".join(["".join(v) for v in spelling_class.values()]))
@@ -87,7 +87,7 @@ def sound_syllable(syllable: str) -> str:
         return "dead"
 
     # get consonants
-    consonants = [i for i in syllable if i in list(thai_consonants_all)]
+    consonants = [i for i in syllable if i in thai_consonants_all]
     if (
         (len(consonants) == 0)
         and ("อ" in syllable)
diff --git a/setup.cfg b/setup.cfg
index 0d701287c..de9810524 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,5 +1,5 @@
 [bumpversion]
-current_version = 5.1.0
+current_version = 5.1.1
 commit = True
 tag = True
 parse = (?P<major>\d+)\.(?P<minor>\d+)\.(?P<patch>\d+)(\-(?P<release>[a-z]+)(?P<build>\d+))?
diff --git a/setup.py b/setup.py
index 06c4d755b..42c6bddb7 100644
--- a/setup.py
+++ b/setup.py
@@ -150,7 +150,7 @@
 
 setup(
     name="pythainlp",
-    version="5.1.0",
+    version="5.1.1",
     description="Thai Natural Language Processing library",
     long_description=LONG_DESC,
     long_description_content_type="text/markdown",
@@ -199,7 +199,7 @@
         ],
     },
     project_urls={
-        "Documentation": "https://pythainlp.org/docs/5.0/",
+        "Documentation": "https://pythainlp.org/docs/5.1/",
         "Tutorials": "https://pythainlp.org/tutorials/",
         "Source Code": "https://github.com/PyThaiNLP/pythainlp",
         "Bug Tracker": "https://github.com/PyThaiNLP/pythainlp/issues",