Given the significant improvements on this:
[color=#FF0000]What is the expected date for the upgrade?[/color]
By not upgrading SVN Dreamhost is not only hurting its customers it is also hurting itself (performance, security, etc.).
From the Release Notes:
Older clients and servers interoperate transparently with 1.9 servers and clients. However, some of the new 1.9 features may not be available unless both client and server are the latest version. There are also cases where a new feature will work but will run less efficiently if the client is new and the server old.
There is no need to dump and reload your repositories. Subversion 1.9 servers can read and write to repositories created by earlier versions. To upgrade an existing server installation, just install the newest libraries and binaries on top of the older ones.
Subversion 1.9 maintains API/ABI compatibility with earlier releases, by only adding new functions, never removing old ones. A program written to any previous 1.x API can both compile and run using 1.9 libraries. However, a program written for 1.9 cannot necessarily compile or run against older libraries.
There may be limited cases where the behavior of old APIs has been slightly modified from previous releases. These are cases where edge cases of the functionality has been deemed buggy, and therefore improved or removed. Please consult the API errata for more detailed information on what these APIs are and what impact these changes may have.