diff --git a/ch6/requirements/lib-py3.10.txt b/ch6/requirements/lib-py3.10.txt
index 2b3ae06..3085098 100644
--- a/ch6/requirements/lib-py3.10.txt
+++ b/ch6/requirements/lib-py3.10.txt
@@ -646,9 +646,9 @@ justext==3.0.1 \
     --hash=sha256:b6ed2fb6c5d21618e2e34b2295c4edfc0bcece3bd549ed5c8ef5a8d20f0b3451 \
     --hash=sha256:e0fb882dd7285415709f4b7466aed23d6b98b7b89404c36e8a2e730facfed02b
     # via trafilatura
-langchain==0.2.16 \
-    --hash=sha256:8f59ee8b45f268df4b924ea3b9c63e49286efa756d16b3f6a9de5c6e502c36e1 \
-    --hash=sha256:ffb426a76a703b73ac69abad77cd16eaf03dda76b42cff55572f592d74944166
+langchain==0.3.7 \
+    --hash=sha256:2e4f83bf794ba38562f7ba0ede8171d7e28a583c0cec6f8595cfe72147d336b2 \
+    --hash=sha256:cf4af1d5751dacdc278df3de1ff3cbbd8ca7eb55d39deadccdd7fb3d3ee02ac0
     # via
     #   langchain-community
     #   ragas
diff --git a/ch6/requirements/lib-py3.11.txt b/ch6/requirements/lib-py3.11.txt
index f5de1c2..cb5f845 100644
--- a/ch6/requirements/lib-py3.11.txt
+++ b/ch6/requirements/lib-py3.11.txt
@@ -634,9 +634,9 @@ justext==3.0.1 \
     --hash=sha256:b6ed2fb6c5d21618e2e34b2295c4edfc0bcece3bd549ed5c8ef5a8d20f0b3451 \
     --hash=sha256:e0fb882dd7285415709f4b7466aed23d6b98b7b89404c36e8a2e730facfed02b
     # via trafilatura
-langchain==0.2.16 \
-    --hash=sha256:8f59ee8b45f268df4b924ea3b9c63e49286efa756d16b3f6a9de5c6e502c36e1 \
-    --hash=sha256:ffb426a76a703b73ac69abad77cd16eaf03dda76b42cff55572f592d74944166
+langchain==0.3.7 \
+    --hash=sha256:2e4f83bf794ba38562f7ba0ede8171d7e28a583c0cec6f8595cfe72147d336b2 \
+    --hash=sha256:cf4af1d5751dacdc278df3de1ff3cbbd8ca7eb55d39deadccdd7fb3d3ee02ac0
     # via
     #   langchain-community
     #   ragas
diff --git a/ch6/requirements/lib-py3.12.txt b/ch6/requirements/lib-py3.12.txt
index b491dce..9e0a68e 100644
--- a/ch6/requirements/lib-py3.12.txt
+++ b/ch6/requirements/lib-py3.12.txt
@@ -634,9 +634,9 @@ justext==3.0.1 \
     --hash=sha256:b6ed2fb6c5d21618e2e34b2295c4edfc0bcece3bd549ed5c8ef5a8d20f0b3451 \
     --hash=sha256:e0fb882dd7285415709f4b7466aed23d6b98b7b89404c36e8a2e730facfed02b
     # via trafilatura
-langchain==0.2.16 \
-    --hash=sha256:8f59ee8b45f268df4b924ea3b9c63e49286efa756d16b3f6a9de5c6e502c36e1 \
-    --hash=sha256:ffb426a76a703b73ac69abad77cd16eaf03dda76b42cff55572f592d74944166
+langchain==0.3.7 \
+    --hash=sha256:2e4f83bf794ba38562f7ba0ede8171d7e28a583c0cec6f8595cfe72147d336b2 \
+    --hash=sha256:cf4af1d5751dacdc278df3de1ff3cbbd8ca7eb55d39deadccdd7fb3d3ee02ac0
     # via
     #   langchain-community
     #   ragas
diff --git a/ch6/requirements/lib-py3.8.txt b/ch6/requirements/lib-py3.8.txt
index 246e7b1..545988c 100644
--- a/ch6/requirements/lib-py3.8.txt
+++ b/ch6/requirements/lib-py3.8.txt
@@ -650,9 +650,9 @@ justext==3.0.1 \
     --hash=sha256:b6ed2fb6c5d21618e2e34b2295c4edfc0bcece3bd549ed5c8ef5a8d20f0b3451 \
     --hash=sha256:e0fb882dd7285415709f4b7466aed23d6b98b7b89404c36e8a2e730facfed02b
     # via trafilatura
-langchain==0.0.27 \
-    --hash=sha256:a39260732b877b223869151db677c08b4b78fb4611c59fc5918f314d0a9d4227 \
-    --hash=sha256:cdaca3a61eb57a76bef990ce3c4615ac06873e83f100bf9c485f6c36e29ed95c
+langchain==0.3.7 \
+    --hash=sha256:2e4f83bf794ba38562f7ba0ede8171d7e28a583c0cec6f8595cfe72147d336b2 \
+    --hash=sha256:cf4af1d5751dacdc278df3de1ff3cbbd8ca7eb55d39deadccdd7fb3d3ee02ac0
     # via ragas
 lazy-imports==0.3.1 \
     --hash=sha256:149500cb1015726f5148155989386b30b425dfd7e48fd156385eb1c9e23887dd \
diff --git a/ch6/requirements/lib-py3.9.txt b/ch6/requirements/lib-py3.9.txt
index 704029e..2dba225 100644
--- a/ch6/requirements/lib-py3.9.txt
+++ b/ch6/requirements/lib-py3.9.txt
@@ -650,9 +650,9 @@ justext==3.0.1 \
     --hash=sha256:b6ed2fb6c5d21618e2e34b2295c4edfc0bcece3bd549ed5c8ef5a8d20f0b3451 \
     --hash=sha256:e0fb882dd7285415709f4b7466aed23d6b98b7b89404c36e8a2e730facfed02b
     # via trafilatura
-langchain==0.2.16 \
-    --hash=sha256:8f59ee8b45f268df4b924ea3b9c63e49286efa756d16b3f6a9de5c6e502c36e1 \
-    --hash=sha256:ffb426a76a703b73ac69abad77cd16eaf03dda76b42cff55572f592d74944166
+langchain==0.3.7 \
+    --hash=sha256:2e4f83bf794ba38562f7ba0ede8171d7e28a583c0cec6f8595cfe72147d336b2 \
+    --hash=sha256:cf4af1d5751dacdc278df3de1ff3cbbd8ca7eb55d39deadccdd7fb3d3ee02ac0
     # via
     #   langchain-community
     #   ragas