How long will iPhoto Libraries be readable?
The recent changes to photo management software motivated me to create a new iPhoto Library for the first time. The old iPhoto Library has 60,000 photos, it's the only cataloging software I have ever used.
For now, the old Library can simply rest on an external HD. But, in the long run, it may became unreadable by Photos 6.x, or by Facebook after Facebook buys Apple, or whatever.
What's the best way to preserve this data in a multi-application readable form?
Mac mini, OS X Mavericks (10.9.3)