How to build a C++ program which can run on RHEL4 without update, RHEL4 with Update1/2/3/4?

[Bo]

I find that my C++ program (built on RHEL4 with Update4) will segment
fault in RHEL4 with Update 3. It is strange. I check RHEL4 Update 4's
release note[1] and it has the following C++ related updates:
---------
gcc-c++-3.4.5-2 => gcc-c++-3.4.6-3
libstdc++-3.4.5-2 => libstdc++-3.4.6-3
----------

My questions are:
1. How to build a C++ program to run on RHEL4, RHEL4 with
Update1/2/3/4?
I guess the answer is 'build C++ program on RHEL 4 without Update',
not 'build C++ program on RHEL 4 with Update4', because libstdc++ is
back-compatible, not fore-compatible.
Am I right?

2. I had assumed that there was no compatibility issue between RHEL 4
Update 3 and 4. But I was wrong.
Do you have any similar experience (C++ compatibility issue between
RHEL 4 Update 3 and Update 4)?

Thanks!

Reference
1. RHEL4 Update 4 Release Note.
http://www.redhat.com/docs/manuals/enterprise/RHEL-4-Manual/release-notes/as-x86/RELEASE-NOTES-U4-x86-en.html

Best Regards,
Xie, Bo