Using the iPhoto Library Upgrader tool
You can use the iPhoto Library Upgrader tool to prepare your library to work with the current version of iPhoto or Photos for OS X.
When you open a library created by an earlier version of iPhoto, you might see a message that says "Library version too old. Please upgrade your library 'iPhoto Library' using the free iPhoto Library Upgrader available from Apple."
The iPhoto Library Upgrader prepares libraries from iPhoto '08 (v7.x) or earlier so that you can use them with the current version of iPhoto or Photos for OS X. If your library was created by iPhoto '09 (v8.x) or later, you don't need to use this tool.
Using the iPhoto Library Upgrader tool
Download and install the tool. When you see a green checkmark above "The installation was successful," click Close.
In the Finder, choose the Go menu and then choose Utilities.
In the Utilities folder, open the iPhoto Library Upgrader.
If the library shown in the window is not the one you want to upgrade, click Choose Library and select the correct iPhoto Library.
Click Continue to upgrade your library.
When you see "Your library can now be upgraded by the current version of iPhoto. Do you want to launch iPhoto?" click Quit.
You can now use the upgraded library in iPhoto ’11 (v9.x) or later, or you can migrate your library to Photos for OS X if you're running OS X Yosemite v10.10.3 or later.