If you upgrade your Domino Server to 11.0.1 FP3 you will notice that your Traveler Service is not starting with the following error message:

/opt/hcl/domino/notes/latest/linux/traveler: error while loading shared libraries: libssl.so.1.1: cannot open shared object file: No such file or directory

The cause is described in the official link and you have to create symlinks for the renamed libraries:

[root@travdevcen02 notesdata]# cd /opt/hcl/domino/notes/latest/linux/
[root@travdevcen02 linux]# ls -la libssl* libcrypto*
-rwxr-xr-x. 1 root root 3366648 Mar 9 00:09 libcrypto-domino.so.1.1
-rwxr-xr-x. 1 root root 687856 Mar 9 00:09 libssl-domino.so.1.1
-rwxr-xr-x. 1 root root 937304 Mar 21 2020 libsslplus.so
[root@travdevcen02 linux]# ln -s libssl-domino.so.1.1 libssl.so.1.1
[root@travdevcen02 linux]# ln -s libcrypto-domino.so.1.1 libcrypto.so.1.1
[root@travdevcen02 linux]# ls -la libssl* libcrypto*
-rwxr-xr-x. 1 root root 3366648 Mar 9 00:09 libcrypto-domino.so.1.1
lrwxrwxrwx. 1 root root 23 Mar 10 09:45 libcrypto.so.1.1 -> libcrypto-domino.so.1.1
-rwxr-xr-x. 1 root root 687856 Mar 9 00:09 libssl-domino.so.1.1
-rwxr-xr-x. 1 root root 937304 Mar 21 2020 libsslplus.so
lrwxrwxrwx. 1 root root 20 Mar 10 09:45 libssl.so.1.1 -> libssl-domino.so.1.1
[root@travdevcen02 linux]#

Afterwards HCL Traveler will start again.