Bukkit

v1.5 - April 15, 2012

• refactored storage subsystem in preparation for home invite feature
• coded full YAML backend on new storage subsystem; storage type YAML for individual YAML files per object (home/spawn/player) or YAML_SINGLE_FILE for a large single data file. YAML storage types are cached in memory for fast, efficient access. You can use the backup/restore feature to backup an existing SQL database, then convert to YAML and restore if you want to switch.
• Ticket #28: home invite feature enhancement. Local testing works good, but needs mass-testing so I'm looking forward to feedback on this feature. Read the documentation.
• Ticket #77: show MC spawn (use /spawnlist -m)
• added /setmapspawn for changing a map's spawn point (not really useful for HSP in any way, just a general utility command)
• added /groupquery command for troubleshooting group problems
• added /homelistother command to list other people's homes (permission: hsp.command.homelistother, alias: /hlo)
• BREAKING CHANGE: old-style permission "hsp.command.xxx.use" no longer works; use new-style "hsp.command.xxx" (old-style permission has been deprecated since 1.0 six months ago, finally cleaning up the code)
• Ticket #72: fixed WorldGuard compatibility to work with newest WorldGuard 5.5 changes
• added Dutch translation; locale nl (thanks @Dunncann!)

Full Changelog

Do not use the HomeInvite feature in 1.5, the command syntax has changed in 1.5.1 (for the better).

http://dev.bukkit.org/server-mods/homespawnplus/files/26-v1-5-1/

If you aren't using the HomeInvite feature, then 1.5 is just as good as 1.5.1, no need to update to 1.5.1.