I'm using the multiprotocol client class, & I simply replaced the 525 jar in my classpath with the 530 version.
When I connect to a host using explicit FTPS (have not tried other protocols yet), I get the following NPEx:
ERROR [ConnectTask] 27 Sep 2018 22:27:30.068 : 1:Connect[dropbox-ssl.redhat.com:21] failed : null
java.lang.NullPointerException
at com.enterprisedt.net.ftp.ssl.SSLFTPClient.enableCipherSuites(SSLFTPClient.java:1181)
at com.enterprisedt.net.ftp.async.internal.ConnectFTPSETask.preConnectConfigure(ConnectFTPSETask.java:229)
at com.enterprisedt.net.ftp.async.internal.ConnectTask.connect(ConnectTask.java:153)
at com.enterprisedt.net.ftp.async.internal.ConnectTask.run(ConnectTask.java:216)
at com.enterprisedt.net.ftp.async.internal.FTPTaskProcessor$b.run(FTPTaskProcessor.java:593)
java.lang.NullPointerException
at com.enterprisedt.net.ftp.ssl.SSLFTPClient.enableCipherSuites(SSLFTPClient.java:1181)
at com.enterprisedt.net.ftp.async.internal.ConnectFTPSETask.preConnectConfigure(ConnectFTPSETask.java:229)
at com.enterprisedt.net.ftp.async.internal.ConnectTask.connect(ConnectTask.java:153)
at com.enterprisedt.net.ftp.async.internal.ConnectTask.run(ConnectTask.java:216)
at com.enterprisedt.net.ftp.async.internal.FTPTaskProcessor$b.run(FTPTaskProcessor.java:593)
ERROR [InternalConnectCallback] 27 Sep 2018 22:27:30.070 : Disconnected
null
ERROR [FTPTaskProcessor] 27 Sep 2018 22:27:30.070 : FTPThread[FTPThread_edt_1] - task 1:Connect[dropbox-ssl.redhat.com:21] failed : null
com.enterprisedt.net.ftp.async.internal.a
at com.enterprisedt.net.ftp.async.internal.ConnectTask.run(ConnectTask.java:271)
at com.enterprisedt.net.ftp.async.internal.FTPTaskProcessor$b.run(FTPTaskProcessor.java:593)
com.enterprisedt.net.ftp.async.internal.a
at com.enterprisedt.net.ftp.async.internal.ConnectTask.run(ConnectTask.java:271)
at com.enterprisedt.net.ftp.async.internal.FTPTaskProcessor$b.run(FTPTaskProcessor.java:593)
If you need me to turn on debug level trace, or you need a simple testcase with source code to show what I'm doing, just let me know!