Many of the 1950s, 1960s and early 1970s episodes of this series are lost.
Its unclear how many of the original live episodes that were recorded and archived still survive as of early 2019, due to a notorious and ruthless near total culling of the BBC Archive's Children's Television section asset holdings, in the early 1990s. Seemingly, the Archive purge was initiated without consultation with the BBC's Children Programming Department, resulting in many other pre-1990s children's programmes being wiped and or destroyed, aka "lost" forever.
The series was later soft-rebooted in early 2020, initially for a 10 week run, with very little changes to the original format, bar a major revision of the prize element of the "Double or Drop" (Cabbages) game. The 2020s version was pre-recorded, and each episode was now around 45-50 minutes long. Also the end of each series now included a compilation of surplus "cut for time" material - generally the Crackerjack Players sketches that would usually match those previous episodes, where they'd ppreviously appeared in completely different costumes for the goodbye finale, for no apparent reason, apart from a now obviously cut sequence.
For the 2021 series 2, recorded under covid restrictions, no really obvious drastic changes needed to be made to the production. The vast set already used a huge studio, so social distancing wasn't an issue. Contestant podiums and their studio floor positions were revised to the social distance amount of 2 metres. Both Sam and Mark, and the Crackerjack Players, appeared to be in a social bubble as they were in unavoidable close contact due to the nature of hosting and performing in sketches. In "Double or Drop", a "Cabbage Monster" full body costume was introduced to give out the wrong answer cabbages to the contestants. Guest hosts, and third party performers were kept socially distanced. Also, the usual studio audience of children, parents and guardians, were not in the usual studio seating, although clearing the production crew were there to give at least some form of audience feedback. The audience laughter may well have been enhanced by Crackerjack's sound library of children's laughter, if they weren't watching via video conferencing. Its not yet been officially revealed if the child contestants for the games, during the covid recordings, were actually family and/or friends of the production team, and on screen participants, but for various health and social distancing reasons, it would make logistical sense if the whole overall programme family were being tested anyway, that they drew on the pool of the cast and crew's children, rather than introduce "outsiders" to the covid-secure environment.
The 2020s re-boot with the entire shows now pre-recorded, were now scheduled on the BBC's CBBC channel, at 6pm on Fridays. The original runs live shows were usually on BBC 1 prefaced with "it's friday, its five to five. Its Crackerjack!". The new version was nearly double the length of the original versions, so it's now equal to an old 20 week run.