libssl and libcrypto backward compatible?

No, OpenSSL is not backwards compatible and as you noticed force-feeding libraries that are not the right versions will just make your software die.

Getting the correct expected library versions in place is the right track. You should check with your distribution to see if they have compatibility packages. Some distros have the latest OpenSSL packages, but they also have add-on packages with older libraries to satisfy specific dependencies on older libraries.

There are some binary incompatible changes exist between 0.9.6 and 1.0.0 versions of OpenSSL according to the compatibility table.

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