Although "Red Hat Fuse Supported Configurations"(1) says "JDBC 4.2 Postgresql Driver, Version 9" is certified, JDBC 4.1 driver is specified in the
$FUSE_HOME/system/org/ops4j/pax/jdbc/pax-jdbc-features/1.3.0/pax-jdbc-features-1.3.0-features.xml as follows:

    <feature name="pax-jdbc-postgresql" description="Provides JDBC PostgreSQL DataSourceFactory" version="1.3.0">
        <feature>pax-jdbc-spec</feature>

        <bundle dependency="true">mvn:org.apache.geronimo.specs/geronimo-jta_1.1_spec/1.1.1</bundle>
        <bundle>mvn:org.postgresql/postgresql/9.4.1212.jre7</bundle>
    </feature>

version 9.4.1212.jre7 is the one for JDBC 4.1.
(1) https://access.redhat.com/articles/310603#Red-Hat-Fuse-72

https://jdbc.postgresql.org/download.html
On the site, please click the link "9.4.1212 JDBC 42", then you will get postgresql-9.4.1212.jar.
9.4.1212.jre7 is the one for "9.4.1212 JDBC 41"