java.lang.UnsupportedClassVersionError heroku deploy

I have an application on a hero and I translated it into 13 Java.

It compiles successfully, but cannot start due to errors:

2019-10-19T10:22:41.678012+00:00 app[worker.1]: Error: LinkageError occurred while loading main class Main

2019-10-19T10:22:41.678050+00:00 app[worker.1]:     java.lang.UnsupportedClassVersionError: Preview features are not enabled for Main (class file version 57.65535). Try running with '--enable-preview'

In heroku it is written to register a java version in system.properties

I did it

java.runtime.version=13 --enable-preview Main

I also changed my pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>TelegramBot</groupId>
    <artifactId>TelegramBot</artifactId>
    <packaging>jar</packaging>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.release>13</maven.compiler.release>
    </properties>

    <build>
        <plugins>
            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>appassembler-maven-plugin</artifactId>
                <version>2.1.0</version>
                <configuration>
                    <assembleDirectory>target</assembleDirectory>
                    <programs>
                        <program>
                            <mainClass>Main</mainClass>
                            <name>teemitze-anna-bot</name>
                        </program>
                    </programs>
                </configuration>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>assemble</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.0</version>
                <configuration>
                    <release>13</release>
                    <compilerArgs>--enable-preview</compilerArgs>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <dependencies>
        <!-- https://mvnrepository.com/artifact/org.jsoup/jsoup -->
        <dependency>
            <groupId>org.jsoup</groupId>
            <artifactId>jsoup</artifactId>
            <version>1.12.1</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-simple -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-simple</artifactId>
            <version>1.7.26</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpclient -->
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.5.9</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/commons-httpclient/commons-httpclient -->
        <dependency>
            <groupId>commons-httpclient</groupId>
            <artifactId>commons-httpclient</artifactId>
            <version>3.1</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.json/json -->
        <dependency>
            <groupId>org.json</groupId>
            <artifactId>json</artifactId>
            <version>20180813</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.codehaus.mojo/appassembler-maven-plugin -->
        <dependency>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>appassembler-maven-plugin</artifactId>
            <version>2.1.0</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.telegram/telegrambots -->
        <dependency>
            <groupId>org.telegram</groupId>
            <artifactId>telegrambots</artifactId>
            <version>4.3.1</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-core -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>5.4.4.Final</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.17</version>
        </dependency>
    </dependencies>
</project>

Anyway, I can’t understand the reason why the application does not start. I also made sure java version on heroku 13

teemitze@SkyNet:~$ heroku run java -version --app teemitze-anna-bot
 ›   Warning: heroku update available from 7.29.0 to 7.33.3.
Running java -version on ⬢ teemitze-anna-bot... up, run.6463 (Free)
openjdk version "13" 2019-09-17
OpenJDK Runtime Environment (build 13+33)
OpenJDK 64-Bit Server VM (build 13+33, mixed mode, sharing)

What could be the reason? Thank!