At the end of July 1783  Mozart returned to Salzburg (after an absence of nearly three years) to introduce his wife to his father and sister. On 31 October, during his return journey to Vienna with Constanze, Mozart writes to Leopold:
“When we reached the gates of Linz [...] we found a servant waiting there to drive us to old Count Thun’s, at whose house we are now staying. I really can’t tell you what kindnesses the family are showering on us. On Tuesday, November 4th, I am giving a concert in the theatre here and, as I have not a single symphony with me, I am writing a new one at breakneck speed, which must be finished by that time. Well, I must close, because I really must set to work.”
If we follow Mozart’s account literally – and there is no reason why we should not – it thus took him barely five days to compose, supervise the copying of the orchestral parts and (presumably) to rehearse the new symphony in time for its first performance in honour of his host.

As with his accomplished arrangements of Mozart’s piano concertos, Hummel’s mastery is evident on every page of the ‘Linz’ Symphony.

“These editions of transcriptions by Hummel are a very welcome addition to the extensive set of his arrangements of Mozart’s concertos and symphonies published by Edition HH. [They] are fine examples of the important genre of piano transcription of the orchestral and operatic repertoire [and] as such, they are greatly to be treasured by anyone with an interest in the burgeoning piano repertoire of the 19th century.”
The Consort, Vol. 79, 2023

Here in a keyboard arrangement by Johann Nepomuk Hummel.

 Music example (pdf)