ANSWER (invented case; Greek Code of Civil Procedure, KPolD, as in force October 2026)

Step 1 - Which remedy and which period.
The final judgment of the Multi-Member Court of First Instance (ordinary procedure) is appealable to the Court of Appeal (Efeteio) under arts. 511 and 513 par. 1 KPolD. The period is set by art. 518 KPolD.

Step 2 - Which limb of art. 518 applies.
The judgment was served at the plaintiff's initiative on Thursday 16 July 2026. Under art. 518 par. 1 KPolD, the appeal period is thirty (30) days from service of the judgment. The sixty-day period of art. 518 par. 1 applies only to a party residing abroad or of unknown residence. The company is seated in Heraklion, so the 30-day period applies. The two-year period of art. 518 par. 2 (running from publication) applies only if the judgment was never served. Here it was served, so it is irrelevant. The 2 July 2026 publication date does not start the 30-day period.

Step 3 - Starting day (dies a quo).
Under art. 144 par. 1 KPolD, read with arts. 240-241 of the Civil Code (applicable by reference), a period counted in days starts on the day after the event. The day of service, 16 July 2026, is not counted. Day 1 is Friday 17 July 2026.

Step 4 - Counting 30 days.
Day 1 = 17 July. Day 15 = 31 July. Day 30 = 15 August 2026. A period in days expires at the end of its last day (art. 144 par. 1 KPolD with art. 241 Civil Code). The nominal last day is therefore 15 August 2026.

Step 5 - Is the nominal last day a working day?
15 August 2026 is a Saturday (16 July is a Thursday, and 30 days is 4 weeks + 2 days, so Thursday + 2 = Saturday). It is also the public holiday of the Dormition of the Theotokos. Under art. 144 par. 3 KPolD, if the last day of a period is a Sunday, another public holiday or a Saturday, the period expires on the next working day (see also art. 242 Civil Code). 16 August 2026 is a Sunday, so the next working day is Monday 17 August 2026.

Step 6 - Judicial vacation (1 July - 15 September).
The judicial vacation does not suspend the running of the appeal period under art. 518 par. 1. The period runs through the vacation, and the only adjustment is the Saturday/Sunday/holiday rule applied in Step 5. I have not re-checked the text of the vacation provision for this answer. Please check it before relying on this step.

Step 7 - Result.
The last day to file the appeal (appeal to the Court of Appeal of Crete) is Monday 17 August 2026.

RESULT: deadline = 2026-08-17; rule = art. 518 par. 1 KPolD (30 days from service) with art. 144 par. 1 and par. 3 KPolD (day after service; Saturday/Sunday/holiday carry-over to next working day)
