> because there's no "version 1 or newer" clause that allows backdoor change to license like typical GPL case
There is actually, and in CDDL (unlike in GPL) version updates are an opt-out feature rather than being opt-in. This was inherited from the MPL (which the CDDL is based on). See section 4 of the CDDL:
> 4.1. Oracle is the initial license steward and may publish revised and/or new versions of this License from time to time. Each version will be given a distinguishing version number. Except as provided in Section 4.3, no one other than the license steward has the right to modify this License.
> 4.2. You may always continue to use, distribute or otherwise make the Covered Software available under the terms of the version of the License under which You originally received the Covered Software. If the Initial Developer includes a notice in the Original Software prohibiting it from being distributed or otherwise made available under any subsequent version of the License, You must distribute and make the Covered Software available under the terms of the version of the License under which You originally received the Covered Software. Otherwise, You may also choose to use, distribute or otherwise make the Covered Software available under the terms of any subsequent version of the License published by the license steward.
In fact this is the primary argument that people give when arguing that Oracle could very easily make OpenZFS GPL-compatible -- they just need to release a CDDL v2 which says "code under this license is dual-licensed under the GPLv2 and CDDLv1.1". This situation has already happened -- CDDLv1.1 used this mechanism to change the "license steward" from "Sun Microsystems" to "Oracle".
Updates in GPL, thanks to standard boilerplate provided by GPL and used for years, are opt-out.
With CDDL, Oracle declares they have the sole right to provide newer versions of the license. However at no time can they treat it as an "upgrade path" for third party code, and OpenZFS code is explicitly labeled with CDDL 1.0
All of that has no impact on OpenZFS code which remains unencumbered, including by patents (the patent license is, afaik, the part that makes it incompatible with GPL the most).
There is actually, and in CDDL (unlike in GPL) version updates are an opt-out feature rather than being opt-in. This was inherited from the MPL (which the CDDL is based on). See section 4 of the CDDL:
> 4.1. Oracle is the initial license steward and may publish revised and/or new versions of this License from time to time. Each version will be given a distinguishing version number. Except as provided in Section 4.3, no one other than the license steward has the right to modify this License.
> 4.2. You may always continue to use, distribute or otherwise make the Covered Software available under the terms of the version of the License under which You originally received the Covered Software. If the Initial Developer includes a notice in the Original Software prohibiting it from being distributed or otherwise made available under any subsequent version of the License, You must distribute and make the Covered Software available under the terms of the version of the License under which You originally received the Covered Software. Otherwise, You may also choose to use, distribute or otherwise make the Covered Software available under the terms of any subsequent version of the License published by the license steward.
In fact this is the primary argument that people give when arguing that Oracle could very easily make OpenZFS GPL-compatible -- they just need to release a CDDL v2 which says "code under this license is dual-licensed under the GPLv2 and CDDLv1.1". This situation has already happened -- CDDLv1.1 used this mechanism to change the "license steward" from "Sun Microsystems" to "Oracle".