diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2df6fcf..ac0378a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,11 @@ orchestration code; see each submodule's own `CHANGELOG.md`
 [sso-manager-node](https://github.com/theta42/sso-manager-node/blob/master/CHANGELOG.md))
 for what changed inside the apps it composes.
 
+## [v1.35.15] - 2026-08-04
+
+### Fixed
+- **theta-agent re-install failed with "Text file busy"** — setup.sh copied the prebuilt binary over a running agent service, which cp refuses. It now stops the service before copying.
+
 ## [v1.35.14] - 2026-08-04
 
 ### Fixed
diff --git a/setup.sh b/setup.sh
index a11221e..ada2fd8 100755
--- a/setup.sh
+++ b/setup.sh
@@ -1213,6 +1213,9 @@ if [[ "$CFG_THETA_AGENT_ENABLE" == "1" ]]; then
 						sudo sed -i "s|https://sso.example.com|https://${SSO_HOST}|" /etc/theta42/agent.yml
 					fi
 				fi
+				# Stop a running agent before overwriting its binary (cp into a
+				# running executable fails with "Text file busy" on a re-install).
+				sudo systemctl stop theta-agent.service 2>/dev/null || true
 				sudo cp theta-agent-linux-amd64 /usr/local/bin/theta-agent
 				sudo chmod +x /usr/local/bin/theta-agent