diff --git a/README.md b/README.md
index 56405c6..3d0dff1 100644
--- a/README.md
+++ b/README.md
@@ -73,12 +73,12 @@ O núcleo carrega **todos os `*.jar`** em `PITIUPI_HOME/plugins`. Detalhes: [pit
 
 | Ferramenta | Uso |
 | --- | --- |
-| **JDK** com `javac` | Compilação (OpenJDK **25** recomendado; núcleo Java 17) |
+| **JDK** com `javac` | Compilação **Java 17+** (núcleo e plugins usam bytecode 17) |
 | **Apache Ant** | Módulos NetBeans |
 | **python3** | Script `scripts/pitiupi.sh` (ler o catálogo) |
 
 ```bash
-sudo apt install openjdk-25-jdk ant
+sudo apt install openjdk-21-jdk ant
 ./scripts/pitiupi.sh check
 cd pitiupi && ant test    # testes JUnit do núcleo
 ```
diff --git a/docs/documentation/00_quickstart.md b/docs/documentation/00_quickstart.md
index 30c1700..5dacfbf 100644
--- a/docs/documentation/00_quickstart.md
+++ b/docs/documentation/00_quickstart.md
@@ -2,13 +2,14 @@
 
 ## Pré-requisitos
 
-- **JDK completo** (`java` e `javac`) — OpenJDK 25 recomendado; o núcleo usa `javac.source/target=17`, plugins Ant usam 25.
+- **JDK completo** (`java` e `javac`) — **Java 17 ou superior** (17, 21 ou 25). Núcleo e plugins compilam com `javac.source/target=17`.
 - Apache Ant (`pitiupi`, `plugins/chat`, `plugins/screencast`)
 
 Ubuntu / WSL:
 
 ```bash
-sudo apt install openjdk-25-jdk ant
+sudo apt install openjdk-21-jdk ant
+# ou: openjdk-17-jdk
 which javac ant
 ```
 
diff --git a/docs/documentation/03_build_ant_netbeans.md b/docs/documentation/03_build_ant_netbeans.md
index 07c301a..3a6e05e 100644
--- a/docs/documentation/03_build_ant_netbeans.md
+++ b/docs/documentation/03_build_ant_netbeans.md
@@ -3,8 +3,8 @@
 | Módulo | Build | Java |
 | --- | --- | --- |
 | `pitiupi` | Ant | 17 |
-| `plugins/chat` | Ant | 25 |
-| `plugins/screencast` | Ant | 25 |
+| `plugins/chat` | Ant | 17 |
+| `plugins/screencast` | Ant | 17 |
 
 ```bash
 cd pitiupi && ant jar
diff --git a/plugins/chat/nbproject/project.properties b/plugins/chat/nbproject/project.properties
index 45f36e7..18c0c57 100644
--- a/plugins/chat/nbproject/project.properties
+++ b/plugins/chat/nbproject/project.properties
@@ -47,8 +47,8 @@ javac.modulepath=
 javac.processormodulepath=
 javac.processorpath=\
     ${javac.classpath}
-javac.source=25
-javac.target=25
+javac.source=17
+javac.target=17
 javac.test.classpath=\
     ${javac.classpath}:\
     ${build.classes.dir}
diff --git a/plugins/screencast/.idea/misc.xml b/plugins/screencast/.idea/misc.xml
index 59ad060..0623d9d 100644
--- a/plugins/screencast/.idea/misc.xml
+++ b/plugins/screencast/.idea/misc.xml
@@ -1,3 +1,3 @@
 <project version="4">
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_25" project-jdk-name="openjdk-26" project-jdk-type="JavaSDK" />
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_17" project-jdk-name="openjdk-26" project-jdk-type="JavaSDK" />
 </project>
\ No newline at end of file
diff --git a/plugins/screencast/nbproject/project.properties b/plugins/screencast/nbproject/project.properties
index ef9e717..db63554 100644
--- a/plugins/screencast/nbproject/project.properties
+++ b/plugins/screencast/nbproject/project.properties
@@ -45,8 +45,8 @@ javac.modulepath=
 javac.processormodulepath=
 javac.processorpath=\
     ${javac.classpath}
-javac.source=25
-javac.target=25
+javac.source=17
+javac.target=17
 javac.test.classpath=\
     ${javac.classpath}:\
     ${build.classes.dir}
diff --git a/scripts/pitiupi.sh b/scripts/pitiupi.sh
index 6ad53fd..40138ce 100755
--- a/scripts/pitiupi.sh
+++ b/scripts/pitiupi.sh
@@ -240,6 +240,14 @@ check_tools() {
     registry_python validate
     printf 'OK plugins.registry.json\n'
   fi
+  if command -v javac >/dev/null 2>&1; then
+    local javac_major
+    javac_major="$(javac -version 2>&1 | grep -oE '[0-9]+' | head -1)"
+    if [[ -n "${javac_major}" && "${javac_major}" -lt 17 ]]; then
+      printf 'ERRO: javac precisa ser Java 17 ou superior (atual: %s)\n' "$(javac -version 2>&1)" >&2
+      ok=1
+    fi
+  fi
   return "${ok}"
 }