"we've been ironing out some performance issues which we felt would make it an unusable development experience for users"
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we've been ironing out some bundler performance issues which would have degraded the developer experience we're looking to deliver.

"At the time of writing the performance is much more stable and we are aiming to do a new release at the end of this current sprint (end of January) for BladeRunnerJS v0.4"
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We've made some excellent headway on these performance issues and we're aiming to do release BladeRunnerJS v0.4 at the end of January.