# Version compatibility **URL:** \ **Category:** Uncategorized\ **Created:** [June 29, 2014, 12:38pm UTC](https://discuss.kotlinlang.org/t/version-compatibility/559 "2014-06-29T12:38:36Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![kocka](https://avatars.discourse-cdn.com/v4/letter/k/e95f7d/32.png) [@kocka](https://discuss.kotlinlang.org/u/kocka)\ **Post date:** [June 29, 2014, 12:38pm UTC](https://discuss.kotlinlang.org/t/version-compatibility/559/1 "2014-06-29T12:38:36Z")
Hi, I am getting this error message from the compiler while trying to run my tests with spek 0.1.122 (latest at the moment) and kotlin 0.7.1217 (also the latest) Class ‘org/spek/Spek’ was compiled with an incompatible version of Kotlin. **Its ABI version is 15, expected ABI version is 16** This means that the format generated by kotlin compiler is not backward compatible? ---
**Author:** ![geevee](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.kotlinlang.org/geevee/32/1475_2.png) [@geevee](https://discuss.kotlinlang.org/u/geevee)\ **Post date:** [June 30, 2014, 6:21pm UTC](https://discuss.kotlinlang.org/t/version-compatibility/559/2 "2014-06-30T18:21:51Z")
Until Kotlin 1.0 is released, we don't put much effort into preserving backward compatiblity. ---
**Author:** ![kocka](https://avatars.discourse-cdn.com/v4/letter/k/e95f7d/32.png) [@kocka](https://discuss.kotlinlang.org/u/kocka)\ **Post date:** [June 30, 2014, 9:25pm UTC](https://discuss.kotlinlang.org/t/version-compatibility/559/3 "2014-06-30T21:25:04Z")
That's the answer I hoped :) Is there any public roadmap for Kotlin btw? ---
**Author:** ![abreslav](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.kotlinlang.org/abreslav/32/8279_2.png) [@abreslav](https://discuss.kotlinlang.org/u/abreslav)\ **Post date:** [July 1, 2014, 4:36am UTC](https://discuss.kotlinlang.org/t/version-compatibility/559/4 "2014-07-01T04:36:32Z")
Not really. What would you like to know? ---
**Author:** ![jrenner](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.kotlinlang.org/jrenner/32/1472_2.png) [@jrenner](https://discuss.kotlinlang.org/u/jrenner)\ **Post date:** [July 2, 2014, 5:03pm UTC](https://discuss.kotlinlang.org/t/version-compatibility/559/5 "2014-07-02T17:03:44Z")
How many many milestones are expected before 1.0? ---
**Author:** ![abreslav](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.kotlinlang.org/abreslav/32/8279_2.png) [@abreslav](https://discuss.kotlinlang.org/u/abreslav)\ **Post date:** [July 2, 2014, 7:17pm UTC](https://discuss.kotlinlang.org/t/version-compatibility/559/6 "2014-07-02T19:17:27Z")
As many as may be needed. We trade in quality, not in milestones :) ---
**Author:** ![kocka](https://avatars.discourse-cdn.com/v4/letter/k/e95f7d/32.png) [@kocka](https://discuss.kotlinlang.org/u/kocka)\ **Post date:** [July 2, 2014, 8:21pm UTC](https://discuss.kotlinlang.org/t/version-compatibility/559/7 "2014-07-02T20:21:30Z")
When do you expect a "1.0" and what are the major steps planned till then? ---
**Author:** ![abreslav](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.kotlinlang.org/abreslav/32/8279_2.png) [@abreslav](https://discuss.kotlinlang.org/u/abreslav)\ **Post date:** [July 3, 2014, 8:41am UTC](https://discuss.kotlinlang.org/t/version-compatibility/559/8 "2014-07-03T08:41:20Z")
When: I can't give you a good estimate and don't want to give bad ones. Major steps (language-wise): - reflection - incremental compilation - platform types (no need for annotations to use Java libraries nicely) - full support for modules - full support of inline functions (non-local returns + optmizations + debug support) - support for Java 8’s new features (default methods, streams etc) - design revision (fixing many glitches in the syntax, many changes will be breaking, though cosmetic), this will encorporate lots of feedback we are getting from the users inside and outside JetBrains - many-many bugfixes, of course IDE-wise it’s mostly more automated refactorings/intspections and performance optimizations + better debugger support ---
**Author:** ![Oliver\_Plohmann](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.kotlinlang.org/oliver_plohmann/32/2398_2.png) [@Oliver\_Plohmann](https://discuss.kotlinlang.org/u/Oliver_Plohmann)\ **Post date:** [July 3, 2014, 10:33am UTC](https://discuss.kotlinlang.org/t/version-compatibility/559/9 "2014-07-03T10:33:21Z")
> Major steps (language-wise): - ... - full support for modules ... What kind of modules do you mean in your statement above ("full support for modules")? Do you mean OSGi modules? ---
**Author:** ![abreslav](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.kotlinlang.org/abreslav/32/8279_2.png) [@abreslav](https://discuss.kotlinlang.org/u/abreslav)\ **Post date:** [July 3, 2014, 10:52am UTC](https://discuss.kotlinlang.org/t/version-compatibility/559/10 "2014-07-03T10:52:10Z")
No, I mean compile-time modules, like those you have in the IDE